diff --git a/src/jianda_proxy/config.py b/src/jianda_proxy/config.py
new file mode 100644
index 0000000..5f67fe5
--- /dev/null
+++ b/src/jianda_proxy/config.py
@@ -0,0 +1,70 @@
+import os
+import configparser
+from pathlib import Path
+
+SECTION = "proxy"
+DEFAULTS = {
+    "remote_domain": "git.zz.com",
+    "upstream_host": "62.234.191.215",
+    "upstream_port": "3000",
+    "listen_port": "13000",
+    "listen_host": "127.0.0.1",
+}
+
+
+def get_config_dir():
+    if os.name == "nt":
+        base = os.environ.get("APPDATA", os.path.expanduser("~"))
+    else:
+        base = os.environ.get("XDG_CONFIG_HOME", os.path.expanduser("~/.config"))
+    return os.path.join(base, "jianda-proxy")
+
+
+def _ensure_dir(path):
+    os.makedirs(path, exist_ok=True)
+
+
+def get_config_path():
+    return os.path.join(get_config_dir(), "config.ini")
+
+
+def get_pid_path():
+    return os.path.join(get_config_dir(), "daemon.pid")
+
+
+def get_log_path():
+    return os.path.join(get_config_dir(), "proxy.log")
+
+
+def load_config():
+    path = get_config_path()
+    _ensure_dir(get_config_dir())
+    parser = configparser.ConfigParser()
+    if not os.path.exists(path):
+        parser[SECTION] = dict(DEFAULTS)
+        with open(path, "w") as f:
+            parser.write(f)
+    else:
+        parser.read(path)
+        if SECTION not in parser:
+            parser[SECTION] = dict(DEFAULTS)
+    return parser
+
+
+def set_config_value(key, value):
+    if key not in DEFAULTS:
+        raise ValueError(f"Unknown config key: {key}. Valid keys: {', '.join(DEFAULTS)}")
+    parser = load_config()
+    parser[SECTION][key] = value
+    with open(get_config_path(), "w") as f:
+        parser.write(f)
+
+
+def get_config_value(key):
+    parser = load_config()
+    return parser.get(SECTION, key)
+
+
+def list_config():
+    parser = load_config()
+    return dict(parser[SECTION])
diff --git a/tests/test_config.py b/tests/test_config.py
new file mode 100644
index 0000000..89247f8
--- /dev/null
+++ b/tests/test_config.py
@@ -0,0 +1,82 @@
+import os
+import tempfile
+import pytest
+from configparser import ConfigParser
+from jianda_proxy.config import (
+    get_config_dir,
+    get_config_path,
+    get_pid_path,
+    get_log_path,
+    load_config,
+    set_config_value,
+    get_config_value,
+    list_config,
+    DEFAULTS,
+)
+
+FIXTURES = {
+    "remote_domain": "git.zz.com",
+    "upstream_host": "62.234.191.215",
+    "upstream_port": "3000",
+    "listen_port": "13000",
+    "listen_host": "127.0.0.1",
+}
+
+
+class TestConfigDir:
+    def test_returns_path_with_app_name(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HOME", str(tmp_path))
+        result = get_config_dir()
+        assert "jianda-proxy" in result
+
+    def test_windows_uses_appdata(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("APPDATA", str(tmp_path))
+        monkeypatch.delenv("HOME", raising=False)
+        monkeypatch.delenv("XDG_CONFIG_HOME", raising=False)
+        result = get_config_dir()
+        assert "jianda-proxy" in result
+
+
+class TestConfigCRUD:
+    def test_load_creates_default_config(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        config = load_config()
+        for key, val in FIXTURES.items():
+            assert config.get("proxy", key) == val
+
+    def test_load_creates_config_file(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        load_config()
+        assert (tmp_path / "config.ini").exists()
+
+    def test_set_and_get_value(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        set_config_value("listen_port", "8080")
+        assert get_config_value("listen_port") == "8080"
+
+    def test_set_unknown_key_raises(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        with pytest.raises(ValueError, match="Unknown config key"):
+            set_config_value("nonexistent_key", "value")
+
+    def test_list_config(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        load_config()
+        result = list_config()
+        assert isinstance(result, dict)
+        for key, val in FIXTURES.items():
+            assert result[key] == val
+
+
+class TestPaths:
+    def test_config_path(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        assert get_config_path().endswith("config.ini")
+
+    def test_pid_path(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        assert get_pid_path().endswith("daemon.pid")
+
+    def test_log_path(self, tmp_path, monkeypatch):
+        monkeypatch.setattr("jianda_proxy.config.get_config_dir", lambda: str(tmp_path))
+        assert get_log_path().endswith("proxy.log")