Abstract:Difficult for a certain type of aircraft engine fault diagnosis and higher requirements for maintenance technology is put forward according to the on-condition maintenance, using expert system of artificial intelligence technology design the aircraft engine fault diagnosis expert system. The aircraft engine fault diagnosis expert system using the auto-detection technique test the engine, through intelligent diagnosis realize fault location .The system use the modular design idea for human-computer interaction interface design ,fault knowledge database creation, reasoning mechanism design, knowledge acquisition process design, interpretive program design. This system has realized the rapid positioning of engine failure, improving the maintenance timeliness of engine diagnosis. Ensure the integrity rate of the aircraft engines.