Taking the core of a moving half mould as an example,using the MasterCAM to NC pro-gramming,various NC milling paths such as roughing,semi-finishing,residual machining,finishing,and cleanup processing were designed respectively,and the correctness of the tool paths was veri-fied by simulation.In the programming process,it was necessary to design an auxiliary line in or-der to design a qualified tool path.Flexibly utilizing the inclined descent function in the contour milling command,the reciprocated bidirectional cutting was possible when contour milling was carried out,selecting"milling sequence optimization"option and setting reasonable"percentage of step amount"parameter during surface machining could reduce tool lifting times and improve work efficiency.