The Four-axis machining center needs to play its processing advantages, and it can not be separated from the matching four-axis post-processing software; the tool position data generated by NX can be generated after post-processing analysis to generate NC code. The main contents of this study include: the use of D-H parameter method to design the post-processing algorithm of " Four-axis machining center with A turntable"; the post-processing program based on UG Post Builder is studied, and Vericut is used for simulation verification.