Abstract: The bending fatigue performance of 20CrMnTiH steel carburized gears are investigated by the research utilizing scanning electron microscope(SEM),metallographic microscope,fatigue testing machines,and hardness testers.The results show that these gears predominantly fracture along the root area of the teeth.As the load increases,the bending fatigue life of the 20CrMnTiH carburized gears decreases.When the load reaches 50～100kN,the gear fatigue life increases several times.It is recommended that the material be used in production within this range of loads to maximize its performance.