In order to improve the jet pressure of hydraulic sandblasting and perforating technology and accelerate the exploitation speed of hydraulic sandblasting and perforating technology for unconventional oil and gas reservoir and deep formation,a downhole hydraulic supercharger was developed by combining the downhole pressurization technology and hydraulic sandblasting and perforating technology.In order to ensure the safe work of the supercharger and effective to prevent piston stuck phenomenon occurring due to blocked,the piston chamber fluid domain models in forward stroke and reverse stroke were established according to the structure and working principle of the device,the supercharger characteristics of the supercharger in the working process were analyzed,as well as the relationship between the working frequency and inherent frequency. A downhole hydraulic supercharger functional test was conducted on the ground. The experimental results confirm the feasibility of the device. The results show that in a single stroke of piston motion,the piston motion velocity,the fluid outflow velocity and the fluid pressure in the piston cavity all increase first and then gradually stabilize with time;the working frequency of the supercharger does not coincide with the natural frequency,and will not cause resonance phenomenon.The research results provide reference for the design and optimization of the second generation of downhole hydraulic supercharger.