Through doing a research on a regular triangular cavity milling machining cutter path generation method, a machining cutter path is optimized, and panel machining efficiency is improved. A rough machining path part in the traditional cutter path default by a UG is optimized into a path with no sharp corners. A similar spiral involute mode is adopted, a line-circle head-tail connection mode is used, and a cutter path-a necessity-node tangent arc-shaped cutter path is formed. According to the panel milling machining cutter path generated by the method of the invention, the problem that a cutting section within each cutting cycle in the cutter path has a corner can be solved, smooth transition is adopted between the cycles, and at least 20% machining time can be saved. Besides, when the machining cutter path generated by the method is used for machining, problems that instantaneous impact load of the cutter path is over larger due to inertia, a side wall is likely to over cut and the like can be solved, and the service life of the cutter and the service life of a machine tool are prolonged.