Based on the design requirements of non-overload centrifugal pump, blade outlet angle β2, blade outlet width b2, throat area Ft and the inlet diameter of short blade Di, all of which affects the performance of centrifugal pump with complex impeller were chosen to design nine centrifugal pump models with complex impeller. Numerical simulation of whole flow field based on Fluent was adopted to do orthogonal test, the important order of geometric parameters affect the performance of centrifugal pump with complex impeller. The best design scheme for pump model was acquired. Through the test of specimen of the best design scheme, it demonstrated that the excellent selection by using numerical simulation of whole flow field was non-overload and high efficiency. Orthogonal test based on numerical simulation of whole flow field was verified by the research result.