Abstract: Carburizing and quenching+carburizing treatments including carburizing and oil quenching+tempering, twice carburizing and oil quenching+tempering, carburizing and gas quenching+carburizing and oil quenching+tempering, as well as carburizing and quenching+cryogenic+tempering treatments by adding cryogenic treatment before tempering of the above processes were carried out on normalized 20CrNi2Mo bearing steel. The microstructure, mechanical properties and wear resistance of the bearing steel after different treatments were studied. The results show that the structure of bearing steel after carburizing and quenching+tempering was acicle-like martensite+residual austenite+carbide. The martensite was finer, and the residual austenite decreased under carburizing and gas quenching+carburizing and oil quenching+tempering. The hardness, tensile strength and percentage elongation after fracture of bearing steel under carburizing and gas quenching+carburizing and oil quenching+tempering were higher than those under other two carburizing and quenching+tempering, and the wear marks width and depth were smaller. Compared with that by carburizing and quenching+tempering treatment, the austenite content of bearing steel after carburizing and quenching+cryogenic+tempering treatment decreased, the hardness increased, the wear marks width and depth decreased, and the wear mass loss under 200 N load decreased significantly. The optimal process was carburizing and gas quenching+carburizing and oil quenching+cryogenic+tempering.