Abstract: In order to solve the problem that HNC848 CNC system does not support helical interpolation, three solutions are proposed, One is to use CAM software to generate control code which uses linear interpolation instead of curve interpolation. The other is to create a macro program of helical interpolation by using the user macro program of CNC system. the third is to create a macro program of coordinate translation and rotation to replace the characteristic coordinate system, and the 3-axis NC helical interpolation is used to solve this problem.The correctness and convenience of the three schemes are verified by examples, and their characteristics are analyzed for use in different occasions.