Abstract: The working principle of the full hydraulic brake system is briefly introduced. In view of the frequent problems of accumulator filling in the use of a vehicle driven by a quantitative pump, the HCD model of the brake accumulator filling system is established by using the AMESIM policy platform and the layout of the pipeline in the field. The outlet pressure of the charging value and the inlet pressure of the accumulator are simulated. It is concluded that the pressure loss in the pipeline leads to the actual pressure of the accumulator less than the upper limit pressure of the charging valve, resulting in the shortage of high pressure oil in the accumulator, which causes the frequent phenomenon of liquid filling. At the same time, a hand-held pressure flow tester is used to test the pressure of the charging valve at the scene, and the conclusion is similar to that of the simulation. Through the method of shortening the length of the pipeline and increasing the diameter of the pipeline, the layout of the accumulator and the filling valve is optimized, and the high pressure oil capacity stored in the accumulator can meet the design requirements, and the problem of the frequent filling of the vehicle is solved.