When the charger is plugged into the smart phone which has capacitive touch screen, the common mode noise of charger will interfere the working of touch screen. Sometimes the touch screen is even no response. The interference reason is explained by charger and capacitive touch screen. Then, the test system for anticommonmode noise performance of touch panel is designed. The test system contains a signal generator generating a sweep frequency signal which is used to simulate different common mode noise generated by chargers. The test results show that the higher voltage the handset can endure, the anticommonmode noise performance of touch panel is better. This is consistent with the real touch performance of handsets with charger, which proves the test system is effective.