Thrust magnetic bearing is an important part of magnetic suspension system, which is mainly used to control the axial displacement of the rotor. Designing thrust magnetic bearings with lightweight, low loss and good performance is the goal of engineering.The objective function was established to find the optimal quality of bearings under the constraints of bearing capacity, temperature rise and magnetic density limitation. The optimal structural parameters of bearings were obtained by using corresponding solving method. At the same time, the optimization model was analyzed by using finite element method. The parameters of air gap magnetic density and eddy current loss were obtained at different frequencies, and the influence degree of eddy current under different working conditions was revealed