diff --git a/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts b/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts
index 74d7a425d..539364a3c 100644
--- a/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts
+++ b/packages/runtime-vapor/__tests__/dom/patchProp.spec.ts
@@ -90,13 +90,133 @@ describe('patchProp', () => {
       setStyle(el, 'color: red')
       expect(el.style.cssText).toBe('color: red;')
     })
-    test.fails('shoud set style with object and array property', () => {
+
+    test('should work with camelCase', () => {
+      const el = document.createElement('div')
+      setStyle(el, { fontSize: '12px' })
+      expect(el.style.cssText).toBe('font-size: 12px;')
+    })
+
+    test('shoud set style with object and array property', () => {
       const el = document.createElement('div')
       setStyle(el, { color: 'red' })
       expect(el.style.cssText).toBe('color: red;')
       setStyle(el, [{ color: 'blue' }, { fontSize: '12px' }])
       expect(el.style.cssText).toBe('color: blue; font-size: 12px;')
     })
+
+    test('should remove if falsy value', () => {
+      const el = document.createElement('div')
+      setStyle(el, { color: undefined, borderRadius: null })
+      expect(el.style.cssText).toBe('')
+      setStyle(el, { color: 'red' })
+      expect(el.style.cssText).toBe('color: red;')
+      setStyle(el, { color: undefined, borderRadius: null })
+      expect(el.style.cssText).toBe('')
+    })
+
+    test('should work with !important', () => {
+      const el = document.createElement('div')
+      setStyle(el, { color: 'red !important' })
+      expect(el.style.cssText).toBe('color: red !important;')
+    })
+
+    test('should work with camelCase and !important', () => {
+      const el = document.createElement('div')
+      setStyle(el, { fontSize: '12px !important' })
+      expect(el.style.cssText).toBe('font-size: 12px !important;')
+    })
+
+    test('should work with multiple entries', () => {
+      const el = document.createElement('div')
+      setStyle(el, { color: 'red', marginRight: '10px' })
+      expect(el.style.getPropertyValue('color')).toBe('red')
+      expect(el.style.getPropertyValue('margin-right')).toBe('10px')
+    })
+
+    test('should patch with falsy style value', () => {
+      const el = document.createElement('div')
+      setStyle(el, { width: '100px' })
+      expect(el.style.cssText).toBe('width: 100px;')
+      setStyle(el, { width: 0 })
+      expect(el.style.cssText).toBe('width: 0px;')
+    })
+
+    test('should remove style attribute on falsy value', () => {
+      const el = document.createElement('div')
+      setStyle(el, { width: '100px' })
+      expect(el.style.cssText).toBe('width: 100px;')
+      setStyle(el, { width: undefined })
+      expect(el.style.cssText).toBe('')
+
+      setStyle(el, { width: '100px' })
+      expect(el.style.cssText).toBe('width: 100px;')
+      setStyle(el, null)
+      expect(el.hasAttribute('style')).toBe(false)
+      expect(el.style.cssText).toBe('')
+    })
+
+    test('should warn for trailing semicolons', () => {
+      const el = document.createElement('div')
+      setStyle(el, { color: 'red;' })
+      expect(
+        `Unexpected semicolon at the end of 'color' style value: 'red;'`,
+      ).toHaveBeenWarned()
+
+      setStyle(el, { '--custom': '100; ' })
+      expect(
+        `Unexpected semicolon at the end of '--custom' style value: '100; '`,
+      ).toHaveBeenWarned()
+    })
+
+    test('should not warn for trailing semicolons', () => {
+      const el = document.createElement('div')
+      setStyle(el, { '--custom': '100\\;' })
+      expect(el.style.getPropertyValue('--custom')).toBe('100\\;')
+    })
+
+    test('should work with shorthand properties', () => {
+      const el = document.createElement('div')
+      setStyle(el, { borderBottom: '1px solid red', border: '1px solid green' })
+      expect(el.style.border).toBe('1px solid green')
+      expect(el.style.borderBottom).toBe('1px solid green')
+    })
+
+    // JSDOM doesn't support custom properties on style object so we have to
+    // mock it here.
+    function mockElementWithStyle() {
+      const store: any = {}
+      return {
+        style: {
+          display: '',
+          WebkitTransition: '',
+          setProperty(key: string, val: string) {
+            store[key] = val
+          },
+          getPropertyValue(key: string) {
+            return store[key]
+          },
+        },
+      }
+    }
+
+    test('should work with css custom properties', () => {
+      const el = mockElementWithStyle()
+      setStyle(el as any, { '--theme': 'red' })
+      expect(el.style.getPropertyValue('--theme')).toBe('red')
+    })
+
+    test('should auto vendor prefixing', () => {
+      const el = mockElementWithStyle()
+      setStyle(el as any, { transition: 'all 1s' })
+      expect(el.style.WebkitTransition).toBe('all 1s')
+    })
+
+    test('should work with multiple values', () => {
+      const el = mockElementWithStyle()
+      setStyle(el as any, { display: ['-webkit-box', '-ms-flexbox', 'flex'] })
+      expect(el.style.display).toBe('flex')
+    })
   })
 
   describe('setAttr', () => {
diff --git a/packages/runtime-vapor/src/dom.ts b/packages/runtime-vapor/src/dom.ts
index 6874fa17c..b1c25a8b0 100644
--- a/packages/runtime-vapor/src/dom.ts
+++ b/packages/runtime-vapor/src/dom.ts
@@ -1,6 +1,7 @@
 import { isArray, toDisplayString } from '@vue/shared'
 import type { Block, ParentBlock } from './render'
 
+export * from './dom/style'
 export * from './dom/prop'
 export * from './dom/event'
 export * from './dom/templateRef'
diff --git a/packages/runtime-vapor/src/dom/prop.ts b/packages/runtime-vapor/src/dom/prop.ts
index 77c5170b8..638a64cbc 100644
--- a/packages/runtime-vapor/src/dom/prop.ts
+++ b/packages/runtime-vapor/src/dom/prop.ts
@@ -11,6 +11,7 @@ import {
 } from '@vue/shared'
 import { currentInstance } from '../component'
 import { warn } from '../warning'
+import { setStyle } from './style'
 
 export function recordPropMetadata(el: Node, key: string, value: any): any {
   if (!currentInstance) {
@@ -34,17 +35,6 @@ export function setClass(el: Element, value: any) {
   }
 }
 
-export function setStyle(el: HTMLElement, value: any) {
-  const prev = recordPropMetadata(el, 'style', (value = normalizeStyle(value)))
-  if (value !== prev && (value || prev)) {
-    if (typeof value === 'string') {
-      el.style.cssText = value
-    } else {
-      // TODO
-    }
-  }
-}
-
 export function setAttr(el: Element, key: string, value: any) {
   const oldVal = recordPropMetadata(el, key, value)
   if (value !== oldVal) {
diff --git a/packages/runtime-vapor/src/dom/style.ts b/packages/runtime-vapor/src/dom/style.ts
new file mode 100644
index 000000000..fbe6bf26e
--- /dev/null
+++ b/packages/runtime-vapor/src/dom/style.ts
@@ -0,0 +1,106 @@
+import {
+  camelize,
+  capitalize,
+  hyphenate,
+  isArray,
+  isString,
+  normalizeStyle,
+} from '@vue/shared'
+import { warn } from '../warning'
+import { recordPropMetadata } from './prop'
+
+export function setStyle(el: HTMLElement, value: any) {
+  const prev = recordPropMetadata(el, 'style', (value = normalizeStyle(value)))
+  patchStyle(el, prev, value)
+}
+
+// TODO copied from packages/runtime-dom/src/modules/style.ts
+
+type Style = string | Record<string, string | string[]> | null
+
+function patchStyle(el: Element, prev: Style, next: Style) {
+  const style = (el as HTMLElement).style
+  const isCssString = isString(next)
+  if (next && !isCssString) {
+    if (prev && !isString(prev)) {
+      for (const key in prev) {
+        if (next[key] == null) {
+          setStyleValue(style, key, '')
+        }
+      }
+    }
+
+    for (const key in next) {
+      setStyleValue(style, key, next[key])
+    }
+  } else {
+    if (isCssString) {
+      // TODO: combine with v-show
+      if (prev !== next) {
+        style.cssText = next
+      }
+    } else if (prev) {
+      el.removeAttribute('style')
+    }
+  }
+}
+
+const semicolonRE = /[^\\];\s*$/
+const importantRE = /\s*!important$/
+
+function setStyleValue(
+  style: CSSStyleDeclaration,
+  name: string,
+  val: string | string[],
+) {
+  if (isArray(val)) {
+    val.forEach(v => setStyleValue(style, name, v))
+  } else {
+    if (val == null) val = ''
+    if (__DEV__) {
+      if (semicolonRE.test(val)) {
+        warn(
+          `Unexpected semicolon at the end of '${name}' style value: '${val}'`,
+        )
+      }
+    }
+    if (name.startsWith('--')) {
+      // custom property definition
+      style.setProperty(name, val)
+    } else {
+      const prefixed = autoPrefix(style, name)
+      if (importantRE.test(val)) {
+        // !important
+        style.setProperty(
+          hyphenate(prefixed),
+          val.replace(importantRE, ''),
+          'important',
+        )
+      } else {
+        style[prefixed as any] = val
+      }
+    }
+  }
+}
+
+const prefixes = ['Webkit', 'Moz', 'ms']
+const prefixCache: Record<string, string> = {}
+
+function autoPrefix(style: CSSStyleDeclaration, rawName: string): string {
+  const cached = prefixCache[rawName]
+  if (cached) {
+    return cached
+  }
+  let name = camelize(rawName)
+  if (name !== 'filter' && name in style) {
+    return (prefixCache[rawName] = name)
+  }
+  name = capitalize(name)
+  for (let i = 0; i < prefixes.length; i++) {
+    const prefixed = prefixes[i] + name
+    if (prefixed in style) {
+      return (prefixCache[rawName] = prefixed)
+    }
+  }
+  return rawName
+}