In order to get the sliding bearing with highlevel dimensional accuracy ，two kinds of ironing process for sliding bearing were analyzed by using the method of finite element numerical simulation，and one ironing and three consecutive ironing of the same blank were numerically simulated respectively with the tin bronze as the processing material in Simufact finite element simulation software when the reduction ratio was the same. With dimensional accuracy (expansion of diameter,roundness error and straightness error) of sliding bearing after ironing and the material utilization (bell mouth length) as evaluation indexes, the best forming process was selected and the reliability of simulation was verified by test. The results show that for the tin bronze material, the expansion amount diameter, external roundness error and straightness error of inner axis for onetime ironing is relatively larger, but the straightness error of outer axis for onetime ironing is relatively smaller, and the material utilization rate is also relatively higher, which provides a theoretical basis for the selection of actual production process.