The mixed highorder Fourier noncircular geardriven differential pump has some performance indexes such as discharge, flow pulsation and the maximum modulus of noncircular gear undercut which have many complex influential factors. In order to obtain the best parameters, the basic relations between the order of Fourier noncircular gear and parameters of vanes were established. The mixed highorder Fourier noncircular gear transmission model was built. The subobjective functions of displacement and flow pulsation, and the maximum modulus of noncircular gear undercut were presented. The target evaluation function using the efficacy coefficient method was put forward. And then the multiobjective optimization method was designed based on genetic algorithm to obtain noninferior solutions when the mixed highorder Fourier noncircular geardriven differential pump has the maximum capacity and the minimum pulsation rate which meets the requirement that the maximum modulus of noncircular gear undercut was more than 1.5 in the same pump cavity size. The flow pulsation rate of the optimized differential pump was 22.04% and the displacement was 3870.44mL. Thus, the flow pulsation rate was decreased by 11.3% and the displacement was increased by 3% compared with the existed study.