diff --git a/packages/builder-rsbuild/src/preview/iframe-rsbuild.config.ts b/packages/builder-rsbuild/src/preview/iframe-rsbuild.config.ts
index f32d095..6cb74b6 100644
--- a/packages/builder-rsbuild/src/preview/iframe-rsbuild.config.ts
+++ b/packages/builder-rsbuild/src/preview/iframe-rsbuild.config.ts
@@ -147,21 +147,58 @@ export default async (
     throw new Error('Cache is required')
   }
 
+  let contentFromConfig: RsbuildConfig = {}
   const { content } = await loadConfig({
     cwd: workingDir,
     path: rsbuildConfigPath,
   })
 
+  const { environments, ...withoutEnv } = content
+  if (content.environments) {
+    const envCount = Object.keys(content.environments).length
+    if (envCount === 0) {
+      // Empty useless environment field.
+      contentFromConfig = withoutEnv
+    } else if (envCount === 1) {
+      // Directly use the unique environment.
+      contentFromConfig = mergeRsbuildConfig(
+        withoutEnv,
+        content.environments[0],
+      )
+    } else {
+      // User need to specify the environment first if more than one provided.
+      const userEnv = builderOptions.environment
+      if (typeof userEnv !== 'string') {
+        throw new Error(
+          'You must specify an environment when there are multiple environments in the Rsbuild config.',
+        )
+      }
+
+      if (Object.keys(content.environments).includes(userEnv)) {
+        contentFromConfig = mergeRsbuildConfig(
+          withoutEnv,
+          content.environments[userEnv],
+        )
+      } else {
+        throw new Error(
+          `The specified environment "${userEnv}" is not found in the Rsbuild config.`,
+        )
+      }
+    }
+  } else {
+    contentFromConfig = content
+  }
+
   // Reset `config.source.entry` field, do not use provided entry
   // see https://github.com/rspack-contrib/storybook-rsbuild/issues/43
-  content.source ??= {}
-  content.source.entry = {}
+  contentFromConfig.source ??= {}
+  contentFromConfig.source.entry = {}
 
   const resourceFilename = isProd
     ? 'static/media/[name].[contenthash:8][ext]'
     : 'static/media/[path][name][ext]'
 
-  const merged = mergeRsbuildConfig(content, {
+  const merged = mergeRsbuildConfig(contentFromConfig, {
     output: {
       cleanDistPath: false,
       dataUriLimit: {
diff --git a/packages/builder-rsbuild/src/types.ts b/packages/builder-rsbuild/src/types.ts
index 6d1306b..caea197 100644
--- a/packages/builder-rsbuild/src/types.ts
+++ b/packages/builder-rsbuild/src/types.ts
@@ -43,6 +43,10 @@ export type BuilderOptions = {
    * Enable Rspack's lazy compilation (experimental).
    */
   lazyCompilation?: boolean
+  /**
+   * Which environment to use from the Rsbuild config.
+   */
+  environment?: string
 }
 
 export interface BuilderResult extends BuilderResultBase {
diff --git a/sandboxes/react-16/rsbuild.config.ts b/sandboxes/react-16/rsbuild.config.ts
index 94cc799..27da09d 100644
--- a/sandboxes/react-16/rsbuild.config.ts
+++ b/sandboxes/react-16/rsbuild.config.ts
@@ -2,5 +2,12 @@ import { defineConfig } from '@rsbuild/core'
 import { pluginReact } from '@rsbuild/plugin-react'
 
 export default defineConfig({
+  environments: {
+    web: {
+      source: {
+        entry: { index: './src/index.tsx' },
+      },
+    },
+  },
   plugins: [pluginReact()],
 })