An axial transonic fan with splitter was designed.An optimization method was used to eliminate the influence of the splitter camber shape.The effect of splitter chord length on the aerodynamic performance of the fan rotor was analyzed under the maximum efficiency condition.The results show that the leading edge expanding wave can adjust the length of the main blade boundary layer negative gradient and its strength.Correctly selecting the splitter leading edge position can reduce the boundary loss

control the separation at the rear part of the main blade and produce optimal aerodynamic load distribution.