The water pressure equilibrium system of deep tunnel is composed of groundwater

surrounding rock

grouting ring and lining

which can not be systematically investigated by the traditional methods for the stress and plastic zone of tunnel. The elastoplastic solution for deep tunnel is carried out. The surrounding rock

grouting ring and lining are assumed as isotropic continuous elastoplastic medium. Based on the elastoplastic mechanics

groundwater hydraulics theory and Mohr-Coulomb criterion

the calculation formulas for stress and plastic zone of axisymmetric deep tunnel under the combined action of four factors are deduced. To calculate a deep tunnel

Matlab is adopted to edit routine for the computation. Compared with the calculated results obtained from the traditional solutions

the correctness of deduced formulas is validated; and the defects of traditional methods are indicated. The influence of grouting parameters on plastic zone and the method for deciding optimum thickness of grouting ring are also discussed.