Aiming at the poor position accuracy and low efficiency caused by artificial drilling in the manufacturing process of space rotary part,the control system of a NC drilling machine was designed.The peripheral interface circuits and the PLC program of the system were designed based on SIEMENS 828D NC system.At the same time,the NC drilling process test was launched by programming corresponding Gcode processing program.The test results show the drilling quality and efficiency are largely increased,the NC drilling machine designed can meet the drilling requirements of the space rotary part.