diff --git a/test/host/common/unit_test_harness.py b/test/host/common/unit_test_harness.py
index 698c02cd..cb2cb3c5 100644
--- a/test/host/common/unit_test_harness.py
+++ b/test/host/common/unit_test_harness.py
@@ -59,6 +59,13 @@ VS_ROOTS = [
     r"C:\Program Files\Microsoft Visual Studio\2022\Enterprise",
     r"C:\Program Files\Microsoft Visual Studio\2026\BuildTools",
     r"C:\Program Files\Microsoft Visual Studio\2026\Community",
+    # VS2026 的实际安装目录是 "18"（2026-10 台架实测：vswhere → ...\18\Community，
+    # MSVC 14.51 + SDK 10.0.26100 布局与 2022 一致，cl.exe 路径模式不变）；
+    # 上面两条 "2026" 目录名在本机并不存在，保留以防将来布局回改
+    r"C:\Program Files\Microsoft Visual Studio\18\BuildTools",
+    r"C:\Program Files\Microsoft Visual Studio\18\Community",
+    r"C:\Program Files\Microsoft Visual Studio\18\Professional",
+    r"C:\Program Files\Microsoft Visual Studio\18\Enterprise",
 ]
 SDK_ROOTS = [r"C:\Program Files (x86)\Windows Kits\10"]