Abstract: According to the definition of the three-dimensional swept leading edge,a comparison was made between three different swept transonic rotors to study how different leading edges affect the position and intensity of shock waves,and consequently the performance of fans.Numerical analyses of their flow fields were done,and the results were compared with the study of Hah,C.(1998).The analyses indicate that the aerodynamic sweep can be used to control the shock structure not only at the mid-span but also near the casing by the end-wall effect,and has a different effect on the radial migration of low momentum fluid to the blade tip region.It can be concluded that the rotor leading edge shapes have a significant influence on the shock waves and the performance of fans.