Nowadays, the development of traction motors of high speed train require highly to the bearing's performance. Magnetic-fluid bearing, as a new kind bearing with so many advantages we need, has got lots of attention. And the key problems of Magnetic-fluid bearing are lubrication and reliability. In this paper, we focus on the temperature field problems which influence the lubrication performance as well as the bearing's reliability. Series of models in different sizes are built. Comparing different results, the influence caused by different sizes and different eccentricity is shown at the end. The high-temperature zone becomes much hotter when the eccentricity becomes larger and the fundamental parameters also change the results. Furthermore, the cavitation is also under consideration. These results provide a basis for the further design of the Magnetic-fluid bearing.