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In order to improve the performance of hydraulic braking system, the influencing factors of vehicle braking performance and system principle of mine dump truck were analyzed. Results indicated that the shorter the action time, the smaller the braking distance under certain conditions of maximum braking deceleration and initial braking speed. The simplified model of hydraulic brake system was established, and characteristic analysis was made toward its key component brake pedal valve. The simulation model was built by AMESim to study the influence of brake performance with parameter variation. Conclusion showed that braking system response speed and pressure building time were impacted by several parameters such as accumulator volume, charging pressure and brake pipe length. The methods of decreasing brake action time by residual pressure control were proposed. Correctness of the simulation analysis was verified by experiment results which showed that the action time of brake was reduced and braking distance was shortened with this method. Braking performance was improved greatly, which provided theoretical basis for the design and optimization of similar products.