The launching circuit of certain type of aircraft is a component of weapon control system and it needs testing regularly. To improve the technical levels of the original testing equipment, this paper presents the design of the aircraft launching circuit automatic testing system by adopting the technique of PC/104 Bus. In this paper, the signal of launching circuit and the testing theory are analyzed, and both software and hardware of the testing system are designed. Practical application shows that the system is easy to operate, quick and accurate in testing and provided with potential expansibility.