According to the loading characteristics of esophageal stents and the status of relatively large errors of the test results of esophageal stent fatigue test devices at present, an esophageal stent fatigue test device based on a hydraulic system was designed. In order to determine the relationship between the inlet pressure and the pressure on the stent surface, and to determine the relationship between the inlet pressure and the maximum pressure on the stent surface when the stent diameter changes, ANSYS-CFX was applied to complete some fluid analyses. The simulation results show that the jet range has influence on the relationship between the inlet pressure and the pressure on the stent surface. If the jet range is constant, the relationship is a basically linear relation; while the jet range is changed, the relationship is a nonlinear relation. These data relationships are important reference to implement of the automatic control for the hydraulic system of the experimental device.