As a key component of the piston pump, the distribution valve directly affects the performance and technical indicators of the piston pump. Especially under high-speed and high-pressure conditions, the reliability requirement of the distribution valve is higher. Based on the probability statistical theory and reliability design method to study the inherent reliability of the distribution valve seal pair of the high-speed high-pressure microminiature axial piston pump, the influence of key variables on the inherent reliability of the distribution valve was analyzed, which was further verified by prototype tests. The results show that the material of the housing, the inner and outer diameters of the valve ring, the material properties of the spring, the diameter of the steel wire, the middle diameter of the spring, and the spring preload force have a significant effect on its inherent reliability.