Abstract: According to the design parameters of nuclear reactor coolant pump, the preliminary orthogonal optimization design for main parameters which had influence on the performance of nuclear reactor coolant pump were made by using orthogonal test. According to the results of orthogonal optimization design, a set of the best combination of geometrical parameters and the primary and secondary influence order of the main parameters for the nuclear reactor coolant pump were got. According to the order, the further optimization design of several main parameters was made, and the combination of geometry design parameter for impeller was lastly achieved. The three-dimensional model was established, the inner flow field was simulated, the model pump was designed and manufactured by using similar conversion method and the test research in normal temperature and pressure was done. The results show that the simulation results are similar to the test results, so it shows that the orthogonal optimization design is right.