diff --git a/packages/postcss-pxtransform/__tests__/index.test.js b/packages/postcss-pxtransform/__tests__/index.test.js
index 5b1c7e7ea563..c01e5c7ad8dc 100644
--- a/packages/postcss-pxtransform/__tests__/index.test.js
+++ b/packages/postcss-pxtransform/__tests__/index.test.js
@@ -72,6 +72,13 @@ describe('px2rem', function () {
 
     expect(processed).toBe(expected)
   })
+  
+  it('8 should work on custom baseFontSize', function () {
+    const processed = postcss(px2rem({ platform: 'h5', baseFontSize: 15 })).process(basicCSS).css
+    const expected = '.rule { font-size: 0.5rem }'
+
+    expect(processed).toBe(expected)
+  })
 })
 
 describe('value parsing', function () {
diff --git a/packages/postcss-pxtransform/index.js b/packages/postcss-pxtransform/index.js
index 417c73c0ff53..b9e95e5e5dcd 100644
--- a/packages/postcss-pxtransform/index.js
+++ b/packages/postcss-pxtransform/index.js
@@ -41,7 +41,7 @@ module.exports = postcss.plugin('postcss-pxtransform', function (options = {}) {
   options = Object.assign({}, DEFAULT_WEAPP_OPTIONS, options)
 
   const transUnits = ['px']
-  const baseFontSize = options.baseFontSize || options.minRootSize >= 1 ? options.minRootSize : 20
+  const baseFontSize = options.baseFontSize || (options.minRootSize >= 1 ? options.minRootSize : 20)
   const designWidth = input => typeof options.designWidth === 'function'
     ? options.designWidth(input)
     : options.designWidth
diff --git a/packages/taro-webpack-runner/src/util/index.ts b/packages/taro-webpack-runner/src/util/index.ts
index 35e7e980c24d..798f6a4bf64a 100644
--- a/packages/taro-webpack-runner/src/util/index.ts
+++ b/packages/taro-webpack-runner/src/util/index.ts
@@ -48,7 +48,7 @@ export function parseHtmlScript (pxtransformOption: IPostcssOption['pxtransform'
   const options = pxtransformOption?.config || {}
   const max = options?.maxRootSize ?? 40
   const min = options?.minRootSize ?? 20
-  const baseFontSize = options?.baseFontSize || min > 1 ? min : 20
+  const baseFontSize = options?.baseFontSize || (min > 1 ? min : 20)
   const designWidth = (input => typeof options.designWidth === 'function'
     ? options.designWidth(input)
     : options.designWidth)(baseFontSize)
diff --git a/packages/taro-webpack5-runner/src/webpack/H5WebpackPlugin.ts b/packages/taro-webpack5-runner/src/webpack/H5WebpackPlugin.ts
index 5cf7595400f3..3d2cfff7ff0b 100644
--- a/packages/taro-webpack5-runner/src/webpack/H5WebpackPlugin.ts
+++ b/packages/taro-webpack5-runner/src/webpack/H5WebpackPlugin.ts
@@ -83,7 +83,7 @@ export class H5WebpackPlugin {
     const options = this.pxtransformOption?.config || {}
     const max = options?.maxRootSize ?? 40
     const min = options?.minRootSize ?? 20
-    const baseFontSize = options?.baseFontSize || min > 1 ? min : 20
+    const baseFontSize = options?.baseFontSize || (min > 1 ? min : 20)
     const designWidth = (input => typeof options.designWidth === 'function'
       ? options.designWidth(input)
       : options.designWidth)(baseFontSize)