The nonlinear behavior of stent at work was analyzed. Some assumptions and simplifications were proposed for finite element analysis. Based on that, finite element model creation, selection of material models, boundary conditions and loads of settings were implemented, and the Newton-Raphson method was adopted to complete numerical simulation of stent. Unsymmetrical alternating stress was found that was the major reason for esophagus stent rupture. The fatigue life of different head number of stents were computed by using finite element software. The results show that the more the head number of stent, the longer the fatigue life. The accelerative fatigue experiment in vitro of stent was expressed. The experimental results are consistency with the simulation ones. 