The principle, form and meaning for establishing the workpiece coordinate using G50 were introduced. The actual usage of establishing the workpiece coordinate using G50 was analyzed. Combining with FANUC 0i system, common methods of establishing the workpiece coordinate using G50 were introduced. The solutions to the problems easily appeared in using the methods were provided. The characteristics of G50 and precautions when using G50 were summarized. How to use G50 Flexibly was described. It provided efficient and flexible practical methods for CNC lathe to establish workpiece coordinate system.