Abstract: Aiming at the irregularity of the shape of complex curved surface parts and difficulty in model process,combining with design and processing simulation of pump body bottomcover,the three-dimensional models of parts were established using modelling technology and numerical control programming of MasterCAM software.The tool paths of rough machining and finish machining for the parts were generated,and processing simulation of the parts was obtained and the NC program was generated by post processing.It provided reference for NC programming and machining of similar parts.