Discharge gap is an important parameter in short arc machining, which directly affects the efficiency and quality of the machining, and it is difficult to measure and control. A feed servo control method of cathode tool based on short arc current and voltage is proposed. The design of a state acquisition system for short arc machining was carried out.The accurate acquisition and interaction of current, voltage, temperature and pressure information were realized. Based on the secondary development platform of Huazhong 8 Computer Numerical Control (CNC) system, a special CNC system was developed. The servo control of the anode tool based on feedback information was completed, and the short arc machining verification of aeroengine components was carried out. Relevant test results show that the special CNC system for short arc is stable and reliable, and has good engineering application value.