Layered rock mass is a kind of common rock mass in underground engineering, and its mechanical properties often take on distinct anisotropy. Selecting appropriate yield function and suitable strength parameters variable law, combining elastic constitutive function of anisotropy, then elastoplastic constitutive function of anisotropy is obtained. Gonghe tunnel is numerically modeled by utilizing this constitutive function. Firstly considered the influence of crustal stress and rock property, support design scheme is modified and optimized from these aspects such as deformation of surrounding rock mass, style of failure, magnitude of yield field and bolts tension; secondly considered the influence of construction difficulty and engineering cost from the actual project, it is concluded that the modified design I is better. Modified scheme I is even adopted in the process of tunnel construction. So constitutive model has great effect on the result of calculation, calculation result of appropriate model can provide scientific proof for the actual project.