Abstract: Based on heat transfer principles and thermal elastic-plastic theory, the quenching process simulation of carburized gears had been researched by the finite element method, which was used through the experimental data of 20CrMnTi standard specimen. In order to research the affection of different carburized layer thicknesses to the residual stress formation and distribution, several command streams had been programmed which included creating a model of a columned spur gear and a carburized layer model, the input parameters of various materials, model meshing and the throughout solution process of temperature and stress fields. By changing the different sizes of gears and the thicknesses of carburized layers, the parametric analysis could be realized to the quenching process simulation of the carburized gear. According to the results of numerical analysis, the affection about the residual stress field to gear fatigue damage had been discussed.