Abstract: The residual stress in the surface metamorphic layer of 18CrNiMo7-6 alloy steel treated by carburizing + heat treatment + shot peening after stripping was finite element simulated. Then modificated by finite element matrix after test verification. The residual stress distribution along x and y directions before and after shot peening was studied. The test application of finite element matrix modification was carried out finally. The results show that the relative error between residual stress simulation value and test value after local stripping was less than 10%, accounting that the model was accuracy. After selecting the appropriate correction matrix according to the direction of the residual stress, the plane non-equal biaxial residual stress modified by finite element matrix was close to the initial value. There was the approximate equal biaxial residual stress in the surface metamorphic layer of the unshot peening sample, and the residual stress modification value was not much different from the measured value. There was significant difference between the test residual stress along x and y directions of the shot peening samples. There were non-equal biaxial residual stress in the surface metamorphic layer, and the modification values of the residual stress were all smaller than the measured values.