In this paper, an iron loss prediction model of magnetic bearing considering temperature influence is proposed. A ring specimen test under different frequencies, flux densities and temperatures is used to measure iron loss of steel laminations. Then, an iron loss model with variable coefficients is used for iron loss calculation of the magnetic bearing. Flux densities of different part of magnetic bearing are obtained by using FEM. Finally, the accuracy the proposed iron loss model is validated by an iron loss test on a prototype of molecular pump supported by magnetic bearing.