The gas-driven hydraulic pump uses compressed air as the driving source, utilizing low-pressure gas on the large-area piston end to generate high-pressure liquid on the small-area piston end. Compared to traditional electric pumps and oil cylinders, it offers significant advantages: 1. High hydraulic pressure, up to 500 MPa, enabling pressure testing experiments for various types of valves. 2. It operates smoothly with only 0.5 kg of air source. By adjusting the input air pressure, the output hydraulic pressure can be infinitely adjusted, meeting the high precision requirements for pressure in valve testing. 3. It features an automatic pressure-holding function. The hydraulic pump itself is equipped with inlet and outlet check valves, ensuring stable pressure during valve testing. Additionally, the hydraulic pump has an automatic pressure compensation function. When the pressure in the equipment pipeline decreases, the pump's driving piston automatically activates to compensate for the lost pressure until it stops. 4. It is lightweight and has a simple structure. With fewer hydraulic pump components and seals, as well as a compact size and low weight, it offers convenience for installation, operation, and future maintenance.