diff --git a/packages/core/src/core/postprocess.ts b/packages/core/src/core/postprocess.ts
index 082939d..a563ac5 100644
--- a/packages/core/src/core/postprocess.ts
+++ b/packages/core/src/core/postprocess.ts
@@ -22,7 +22,11 @@ export function postprocessWithUnColor(unColor: string): Postprocessor {
 
 export function importantProcess(): Postprocessor {
   return (util) => {
-    util.entries.forEach(i => i[1] += ' !important')
+    util.entries.forEach(i => {
+      if(i[1] != null && !String(i[1]).includes('!important')){
+        i[1] += ' !important'
+      }
+    })
   }
 }
 // IN-README-END
diff --git a/test/postprocess.test.ts b/test/postprocess.test.ts
index 1439be9..a9a5595 100644
--- a/test/postprocess.test.ts
+++ b/test/postprocess.test.ts
@@ -37,19 +37,26 @@ describe('presetUseful postprocess with unColor', () => {
 })
 
 describe('presetUseful postprocess with important', () => {
-  const code = 'bg-red text-blue'
+  const withOutImport = ['bg-red', 'text-blue']
+  const withInImport = ['!text-xl', 'sm:text-sm!', 'important-ma']
+
 
   it('base', async () => {
     const uno = generateUno({
       important: true,
     })
 
-    const { css } = await uno.generate(code, { preflights: false })
+    const { css } = await uno.generate([...withInImport, ...withOutImport], { preflights: false })
 
     expect(css).toMatchInlineSnapshot(`
       "/* layer: default */
+      .important-ma{margin:auto !important;}
       .bg-red{--un-bg-opacity:1 !important;background-color:rgba(248,113,113,var(--un-bg-opacity)) !important;}
-      .text-blue{--un-text-opacity:1 !important;color:rgba(96,165,250,var(--un-text-opacity)) !important;}"
+      .\\\\!text-xl{font-size:1.25rem !important;line-height:1.75rem !important;}
+      .text-blue{--un-text-opacity:1 !important;color:rgba(96,165,250,var(--un-text-opacity)) !important;}
+      @media (min-width: 640px){
+      .sm\\\\:text-sm\\\\!{font-size:0.875rem !important;line-height:1.25rem !important;}
+      }"
     `)
   })
 })