One type of military radar is a complex electronic equipment, the service time of a certain type of military radar has increased year by year, and the faults in the use process have increased significantly. Due to the weak maintenance capability at the grass-roots level, the maintenance support of the radar basically depends on factory support, and the timeliness and effectiveness can’t meet the needs of the army, which seriously restricts the formation of the combat effectiveness of the radar unit. In order to solve the problem of difficult maintenance of radar in grass-roots units and improve the comprehensive support ability of radar, a portable fault diagnosis system is developed. The system is composed of signal acquisition board, embedded motherboard, power management module and human-computer interaction module. Neural network technology is used to realize rapid fault diagnosis. It solves the problems of the existing radar maintenance equipment, such as huge volume, complex supporting equipment, high price, complex operation and so on. The experimental results show that the system realizes the miniaturization and intellectualization of fault diagnosis platform, has high fault diagnosis efficiency, and can quickly improve the maintenance and support ability of radar.