Abstract: The unified strength theory constitutive model can be embedded nonlinear finite element software ABAQUS for providing the user subroutine second development function. A numerical test using thick wall cylinder as an illustration is completed, which gives the theoretical resolution and three dimension analysis of tunnel excavation．All numerical results indicate that the approach of adding the model to the ABAQUS enriches the material element library and enhances the computation efficiency and precision, meanwhile, by the example verification, the tunnel excavation simulation demonstrates that considering influences of middle main stress in geotechnical engineering, the method can fully utilize the material strength enough, guide the engineering practice and reduce investment outlay.