Abstract: In this paper, the contact elements in software ANSYS are used to simulate the interference fits for the impeller and the shaft in a high temperature reactor（HTR） primary helium circulator. Initial finite element magnitude of interference could be defined by adjusting these contact elements’ real constants, The simulations have been carried for different magnitude of interference, different friction coefficients and different impeller rotational speeds, contact pressure distributions on the fitting surface under these parameters are given. The results show that contact pressure changes along the circumferential direction periodically and it increase with the increase of magnitude of interference linearly. The higher rotational speed of impeller is, the lower contact pressure is on fitting surface close to the hub side and higher contact pressure is close to the shroud.