In order to acquire the main structure parameters impacting on performance of vortex pump and optimize the performance of the vortex pump, the orthogonal testing method was introduced. Impeller outer diameter D2, blade number Z, width of blade b2, impeller outlet blade angle β2 and impeller inlet blade angle β1 were chosen to be the main factors. So 16 sets of programs with 16 type of impellers were designed according to L16（45）orthogonal table. Optimum value range of each factor was preliminarily obtained through range analysis. Quadratic orthogonal test was conducted to investigate the effects of main factors and acquire the primary and secondary factors of the design parameters on the vortex pump, and an optimization scheme for further design was obtained. The internal flow field and experimental results of optimization scheme were compared with the original model, and it showed that pump inlet produced two back-flows with different degree; the back-flow loss of optimal model was less than that of the original model; the efficiency and the head of optimal model are both higher than those of the original model 4.2 percentage points and 10m, respectively. The improved efficiency and head can meet the design requirements. The orthogonal testing method has some feasibility to the performance optimization of vortex pump.