In order to reduce cavitation erosion, a water hydraulic pressure relief valve is generally designed with multistage serial throttles, which causes the difficulties to process, the impossibility to seal simultaneously and the problems of reliability and stability. According to this, a novel water hydraulic pressure relief valve, which mainly consists of two poppets, two springs, a double-stage seat, a body and two caps, is developed. The working principle of the valve is presented. A mathematical model is built and numerical studies are carried out to study the valve's dynamic performances as well as it' s influencing factors, such as spring compression and constant, damping parameters, etc. The results show that: (1) the input flow exerts great effects on the working pressure, the pressure ratio of the upstream and downstream of throttle 1 is about 3.5 and the cavitation index of throttle 1 is about 0.4; (2) the spring constant and pre-compression as well as the damping parameters have great effects on the valve's performance; (3) the new design has a good static and dynamic performance: the pressure range 6-16MPa, the overshoot is less than 17.6%, the transition time is 26ms, the response time is 2.5ms.