With the continuous improvement on the performance of air-to-air missile and the application of various portable guidance and non-guided munitions, the threats faced by military aircraft are further complicated and serious. Active protection system has the unique advantage of actively destroying incoming threats, which can transformative improve the self-defense capability. The concept of the airborne active protection system, the development of the technology and equipments in foreign countries are imposed, which provide references to airborne self-defense development in the future.