In order to further improve the jet pressure of hydraulic sandblasting perforation technology and get rid of the difficulties of traditional surface pressurization method for deep formation rock fracturing due to the difficulty of pressure transmission and high energy consumption,a downhole hydraulic supercharger was designed based on the actual perforation process requirements.According to the structure and working principle of the downhole hydraulic supercharger,considering the influence of the leakage layer between the piston and the piston cylinder on the pressurization effect,the mathematical model and the whole basin model of the pressurization cylinder were established,and the pressurization characteristics of the pressurization cylinder were numerically simulated by using the dynamic grid technology.The results show that during the pressurization process,the pressure of the pressurized chamber and the outflow velocity of the fluid firstly increase with time and then gradually show the law of high-frequency periodic fluctuation.The pressure of the pressurized chamber and the outflow velocity of the fluid increase with the increase of the input pressure and the effective area ratio of the low-pressure chamber to the pressurized chamber fluid,and the pressure of the pressurized chamber is approximately equal to the product of the input pressure and the effective area ratio.The thickness of the leakage layer has great influence on the fluctuation of the pressure of the pressurized chamber and the velocity of the fluid outflow.The research results provide reference for the structure design and parameters optimization of the later turbocharger.