The membership function and the fuzzy deadline set are imported into the plastic yield function to solve the loading-unloading problem in which the Von Mises yield criterion is adopted to deduce the fuzzy plastic yield function. Taken the strain rate into consideration, the fuzzy elastic -plastic constitutive model is obtained. The advantages of this model are consecutive with the changes of the membership, simple in expression and clear in route of loading and unloading. In analyzing Steel panele under the interior cyclic loading based on the model, the numerical solutions are obtained by the finite element method. It is shown that the cyclic loading process could be simulated well by the model and it is an effective way to solve the consecutive elasto-plastic problem under cyclic loading.