In this paper a practical CAD/CAPP/CAM integrated system is introduced. This system has been developed by mechanical designers, process planners and NC progragmmers on the basis of a commercial CAD/CAM software named Pro/ENGINEER. It consists of three subsystems： Feature Recognition Subsystem, CAPP Subsystem and Automatical CAM Subsystem. In Feature Recognition Subsystem, machining features information of a part is obtained from a three dimensional part. In CAPP Subsystem, machining features information is analyzed, sets and sequences of the process planning are created automatically, tool and cutting parameters for each sequence are selected from tools library, the order of sequences is arranged. In Automatical CAM Subsystem, NC sequences for machining the part are created automatically according to the CAPP result. After the NC sequences in the machining process being simulated, the file of cutter location data is generated. Finally through a post processor, the NC code file is output and transmitted to a NC machine to machine the part.