Abstract: The lead screw is the key core components of the electric execution system, especially the ball screw requires the comprehensive mechanical properties of high hardness, high wear resistance and high toughness of the heart, of which the medium frequency surface quenching has become an important process of product production.This paper introduces the medium frequency quenching process test of GCr15SiMn and GCr15 bearing steel ball screw with an outer diameter of 63mm. Through the analysis of the process and results, the technical characteristics and technological rules of surface quenching of bearing steel ball screw are understood.