diff --git a/packages/compiler-sfc/src/compileStyle.ts b/packages/compiler-sfc/src/compileStyle.ts
index b61c46f3..25b8d419 100644
--- a/packages/compiler-sfc/src/compileStyle.ts
+++ b/packages/compiler-sfc/src/compileStyle.ts
@@ -5,7 +5,8 @@ import scopedPlugin from './stylePluginScoped'
 import {
   processors,
   StylePreprocessor,
-  StylePreprocessorResults
+  StylePreprocessorResults,
+  PreprocessLang
 } from './stylePreprocessors'
 
 export interface StyleCompileOptions {
@@ -15,7 +16,7 @@ export interface StyleCompileOptions {
   map?: object
   scoped?: boolean
   trim?: boolean
-  preprocessLang?: string
+  preprocessLang?: PreprocessLang
   preprocessOptions?: any
   postcssOptions?: any
   postcssPlugins?: any[]
diff --git a/packages/compiler-sfc/src/stylePreprocessors.ts b/packages/compiler-sfc/src/stylePreprocessors.ts
index e391c6b7..2c7b3702 100644
--- a/packages/compiler-sfc/src/stylePreprocessors.ts
+++ b/packages/compiler-sfc/src/stylePreprocessors.ts
@@ -104,7 +104,9 @@ const styl: StylePreprocessor = {
   }
 }
 
-export const processors: Record<string, StylePreprocessor> = {
+export type PreprocessLang = 'less' | 'sass' | 'scss' | 'styl' | 'stylus'
+
+export const processors: Record<PreprocessLang, StylePreprocessor> = {
   less,
   sass,
   scss,