For the application of STEP-NC in NC system, an STEP-NC code translator is exploited. Firstly, summarizes the limitation of conventional standard ISO6983 and the superiority of STEP-NC. After an analysis on two different generating methods of STEP-NC program, introduces the exploited STEP-NC code translator based on ISO14649. According to inner logical relation, the code translator is composed by six functional modules, an operating principle chart is presented, function and realizing method of every module is disserted on. At last, exampled with a program which includes planar face, pocket, slot, Bezier surface and replicate feature of round hole, planning the whole toolpath of the program using extracted information about workingstep, feature and operation by the exploited STEP-NC code translator. A cutting simulation is made to the toolpath and the workpiece model. The result proves the feasibility of the STEP-NC code translator.