Abstract: Numerical simulation of the overall performance for a multistage fan was carried out with the computational fluid dynamics(CFD) code developed indigenously.This work was involved with the engine matching and the validation of the code reliability and accuracy.The k-ε turbulence model was introduced,and the source terms in k-ε turbulence model were treated implicitly to relieve the stiffness of k-ε equations.A mixing plane was set for the communication between adjacent blade rows.The code was first verified against a single-stage fan,and then compared with the commercial software and experiments.Further validation was conducted on a four-stage fan.By analyzing the results,it's found that the property of code is good,but the shortcomings caused by the mixing plane need to be improved.