diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b02121..e9f6e69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
 ## 1.12.1 (2024-00-00)
 
 - `deleteFile`: Remove unnecessary file existence checks
+- `joinFilePath`: Responding to parent dir paths
+- cleanup: Remove redundant codes
 
 ## 1.12.0 (2024-04-12)
 
diff --git a/lib/index.ts b/lib/index.ts
index b2c82dd..bc899a2 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -88,7 +88,7 @@ export default class FsMan {
 			return FsMan.toValidFilePath(win32.join(...paths), true);
 		}
 
-		return FsMan.toValidFilePath(paths.join('/'), false);
+		return FsMan.toValidFilePath(posix.join(...paths), false);
 	}
 
 	static getFilePathLevel(filePath: string): number {
diff --git a/test/common.spec.ts b/test/common.spec.ts
index ab2ed6c..ed1ebb1 100644
--- a/test/common.spec.ts
+++ b/test/common.spec.ts
@@ -67,10 +67,15 @@ describe('fsman', () => {
 
 	it('joinFilePath', (done) => {
 		assert.strictEqual(joinFilePath(true, 'C:\\', 'Windows', 'System32'), 'C:\\Windows\\System32');
+		assert.strictEqual(
+			joinFilePath(true, 'C:\\', 'Windows', '..', 'System32', 'Test.txt'),
+			'C:\\System32\\Test.txt'
+		);
 		assert.strictEqual(joinFilePath(true, 'Users', 'test'), '\\Users\\test');
 		assert.strictEqual(joinFilePath(true, 'C:\\Users\\test'), 'C:\\Users\\test');
 		assert.strictEqual(joinFilePath(false, '/home', 'user', 'Desktop'), '/home/user/Desktop');
 		assert.strictEqual(joinFilePath(false, 'home', '/user', '.bashrc'), '/home/user/.bashrc');
+		assert.strictEqual(joinFilePath(false, 'home', '/user', '..', '.bashrc'), '/home/.bashrc');
 		done();
 	});