An incremental elasto-plastic constitutive model in the form of total stress developed by CHENG Xing-lei et al can effectively reflect the undrained cyclic stress-strain response of the saturated soft clay. In order to simulate the response of the soft clay under complex stress states，a secondary development for the constitutive model is conducted by use of the finite element method. The Newton-Raphson method is applied to solve iteratively the material nonlinear problem; considering a series of key problems such as stress reversing, in programming the model, Euler tangent algorithm is adopted，with a sub-incremental method improving calculation accuracy. The response of the soft clay under axisymmetric stress states is predicted, and the stress-strain relationship curves are received, which is compared with the results given by the unit predicting. The analysis comparison results show that it is in good agreement, verifying the rationality of the finite element program. The finite element program is applied to simulate unconsolidated undrained triaxial tests， and the results are in good agreement with the experiments, which indicates that the finite element program of the constitutive model can describe the undrained stress-strain behavior of the soft clay under triaxial stress states. Furthermore, it can be applied to solve more complex boundary value problems.