In order to meet the needs of the next generation refueling system , an optimizaed hydraulic model of a particular centrifugal fuel pump was developed with spiltter blade. First, the complex impeller model with best hydraulic performance was redesigned by using the CFD(computational fluid dynamics) method iteratively. Then, the full threedimensional numerical simulation was applied to the resulting model. The analysis of the internal flow shows that the splitter blade can depress the vortexes effectively. Based on optimization results, specimen products were made and tests were performed to verify the design. The comparison of test data and simulation results show that the performance of the optimized pump is superior to that of the current one. The complex impeller can improve instability of centrifugal pump at small flow and widen its range of working condition from 1.3 to 2 times of the design flow rate condition. The results of this paper can provide technical support for designing better fuel pumps for other applications.