The machining know-how or knowledge exists in the NC programs if they are generated through experienced workers. To realize autonomous CNC machining, accumulation and representation of such know-how in a reusable way is needed. In this paper, an autonomous machining process analyzer for hole machining is studied. With the method, the machining process can be analyzed and the know-how can be extracted from existing successful NC programs. Specifically, machining feature, operation sequence, and cutting parameters including used tools, feedrate and spindle/cutting speed can be extracted. Based on the proposed method, a prototype system has been developed to verify the feasibility of the know-how extraction.