The piston chamber has compression and expansion in closed volume when it is separated from the process of discharge and suction, which caused cavitations and pressure overshoot or undershoot. In addition, the noise problem caused by flow ripple and pressure pulsation may occur. Therefore, a new valve plate was designed to solve those problems. First of all, the mathematical model of flow characteristic was established to analyze the mechanism of the noise in axial piston pump. Then, the new structure of the valve plate was designed and the structure parameter of triangle notch was optimized. According to the design of valve plate structure, the equation of pressure characteristic in transition region was established. Thereafter, the new valve plate was capable to reduce the pressure pulsation, which was validated by theoretical calculation. Finally, the simulation model of piston pump was developed based on AMEsim to analyze the effects of the new valve plate on flow rate and pressure. Moreover, the simulation model was verified accurately based on the comparison of experiment and simulation results. The flow pulsation rate was calculated in the simulation model with original valve plate and new valve plate under the same working condition. The results showed that the flow pulsation rates with the new valve plate and original valve plate were about 11.47% and 18.22%, respectively, and the flow pulsation rate with the new valve plate was decreased by 6.75% compared with the original one. As a consequence, the results showed that the new valve plate can effectively reduce the fluid borne noise in the axial piston pump. The simulation model can be used in the design of new products, which can lower the cost.