Abstract: The optimization design of the filter used in the cryogenic propellant filling system is discussed in this paper.Under the condition of maintaining the outline dimension and flow area of filter，the optimization designs include the change of the hole in the framework（number，dimension，location）；the improvement of the welding requirement between framework，net and fasten piece; the clarification of the space and location of the welding pot，and the fixation between the axial fasten piece and the axial fasten piece.Then the verifications such as temperature cycle test and double way impulsion test were proposed and completed.The numerical simulation results and the use of previous missions indicate the effectiveness of the optimization.