diff --git a/claude.ps1 b/claude.ps1
index 3523cf5..8ef5c75 100644
--- a/claude.ps1
+++ b/claude.ps1
@@ -2,6 +2,46 @@ param(
     [string]$ApiKey
 )
 
+function ConvertTo-Hashtable {
+    param(
+        [Parameter(ValueFromPipeline = $true)]
+        [object]$InputObject
+    )
+
+    if ($null -eq $InputObject) {
+        return $null
+    }
+
+    if ($InputObject -is [System.Collections.IDictionary]) {
+        $table = @{}
+        foreach ($key in $InputObject.Keys) {
+            $table[$key] = ConvertTo-Hashtable $InputObject[$key]
+        }
+        return $table
+    }
+
+    if (
+        $InputObject -is [System.Collections.IEnumerable] -and
+        -not ($InputObject -is [string])
+    ) {
+        $items = @()
+        foreach ($item in $InputObject) {
+            $items += ,(ConvertTo-Hashtable $item)
+        }
+        return $items
+    }
+
+    if ($InputObject -is [psobject]) {
+        $table = @{}
+        foreach ($property in $InputObject.PSObject.Properties) {
+            $table[$property.Name] = ConvertTo-Hashtable $property.Value
+        }
+        return $table
+    }
+
+    return $InputObject
+}
+
 if ([string]::IsNullOrWhiteSpace($ApiKey)) {
     $secure = Read-Host "请输入 API Key" -AsSecureString
     $ptr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
@@ -27,19 +67,15 @@ $data = @{}
 if (Test-Path $SettingsFile) {
     $raw = Get-Content $SettingsFile -Raw -ErrorAction Stop
     if (-not [string]::IsNullOrWhiteSpace($raw)) {
-        $parsed = $raw | ConvertFrom-Json -Depth 100
-
-        $data = @{}
-        foreach ($p in $parsed.PSObject.Properties) {
-            $data[$p.Name] = $p.Value
-        }
+        $parsed = $raw | ConvertFrom-Json
+        $data = ConvertTo-Hashtable $parsed
     }
 }
 
-if ($data.ContainsKey("env") -and $null -ne $data["env"]) {
+if ($data.ContainsKey("env") -and $data["env"] -is [System.Collections.IDictionary]) {
     $envTable = @{}
-    foreach ($p in $data["env"].PSObject.Properties) {
-        $envTable[$p.Name] = $p.Value
+    foreach ($key in $data["env"].Keys) {
+        $envTable[$key] = $data["env"][$key]
     }
 } else {
     $envTable = @{}
diff --git a/tests/test_config_dirs.py b/tests/test_config_dirs.py
index f2cae29..45cddfc 100644
--- a/tests/test_config_dirs.py
+++ b/tests/test_config_dirs.py
@@ -1,4 +1,9 @@
 import pathlib
+import json
+import os
+import shutil
+import subprocess
+import tempfile
 import unittest
 
 
@@ -36,6 +41,46 @@ class ConfigDirTests(unittest.TestCase):
         self.assertIn("`CODEX_HOME`", content)
         self.assertIn("`CLAUDE_CONFIG_DIR`", content)
 
+    def test_claude_ps1_preserves_existing_env_on_windows_powershell(self) -> None:
+        temp_dir = tempfile.mkdtemp(prefix="provider-setup-claude-")
+        self.addCleanup(lambda: shutil.rmtree(temp_dir, ignore_errors=True))
+
+        settings_file = pathlib.Path(temp_dir) / "settings.json"
+        settings_file.write_text(
+            json.dumps({"env": {"EXISTING": "1"}}, ensure_ascii=False),
+            encoding="utf-8",
+        )
+
+        env = os.environ.copy()
+        env["CLAUDE_CONFIG_DIR"] = temp_dir
+
+        completed = subprocess.run(
+            [
+                "powershell",
+                "-ExecutionPolicy",
+                "Bypass",
+                "-File",
+                str(REPO_ROOT / "claude.ps1"),
+                "-ApiKey",
+                "test-key",
+            ],
+            cwd=REPO_ROOT,
+            env=env,
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+
+        self.assertEqual(
+            completed.returncode,
+            0,
+            msg=f"stdout:\n{completed.stdout}\n\nstderr:\n{completed.stderr}",
+        )
+
+        data = json.loads(settings_file.read_text(encoding="utf-8-sig"))
+        self.assertEqual(data["env"]["EXISTING"], "1")
+        self.assertEqual(data["env"]["ANTHROPIC_AUTH_TOKEN"], "test-key")
+
 
 if __name__ == "__main__":
     unittest.main()