The emergency lighting system provides illumination for the passengers to emergency evacuation and works automatically when the aircraft power fails, so the override time and method of emergency lighting has direct influence to the efficiency of passengers' evacuation. At present, the emergency lighting on civil aircraft was mostly overridden by the failure of emergency power supply charging bus, which limits the opening time of emergency lighting and has risk on airworthiness certification. This article introduces a new override method of emergency lighting and interprets the design theory and control logic in detail. The override circuit design of emergency lighting can improve the airworthiness and reduce the research cost of aircraft, and can provide guidance for the design of emergency lighting on civil aircraft.