The fire protection detection system of a civil aircraft consists of detection system,fire extinguishing system.Fire protection system is able to detect fire,monitor some areas,and give a warning about overheating,smoke or fire for designated protection area.Once it detect dangerous situations such as overheating,smoke or fires in protection zones,the system will give a warning to the pilot so that he can adopt corresponding processing program. The system can provide fire extinguishing measures to restrain or extinguish fire, ensuring the safety of the aircraft and people.The system can detect the working state of the equipment, make fault diagnosis, display and record system failure during a flight and make fault isolation.On the ground and during flight, the system provides measures to make crew test equipment state, ensuring the normal operation of the system and the safety of the plane.