In order to realize highefficient production of brake camshaft, the contour accuracy and technical requirements were studied, the milling method for the cam profile of the brake camshaft based on C8051F020 was proposed.In the CNC system upper computer, humancomputer interaction was achieved, and time divisioncoarseinterpolation was used to separate the cam contour into tiny line segments which were expressed in coordinates. In the MCU, fine interpolation arithmetic was done for line segments generated by the PC, at the same time, the control signals were received and then corresponding commands were executed. Experimental tests show that the numerical control system performance is stable, and the machining efficiency and machining quality can meet the production requirement. Therefore the brake camshaft milling CNC system can be used widely in the practical production.