In this paper, an analytical model and optimization including magnetic flux leakage(MFL) for an integrated radial/thrust magnetic bearing(IRTMB) without thrust disk is proposed. Firstly, an analytical method based on equivalent magnetic circuit for IRTMB structure is built. Secondly, the optimization for flux leakage coefficients is conducted using sequential quadratic programming method, a set of optimization variables are suggested. Finally, the flux distribution of initial and optimized structure are compared.