The invention relates to a liquid oxygen temperature zone cold helium pressurization system. In the system, a pressurized gas cylinder 3 is immersed in a liquid oxygen storage tank 1, and can fully exchange heat with liquid oxygen. The b pressurized gas cylinder 3 is arranged, in the liquid oxygen storage tank 1, near the upper part of the storage tank, after a few seconds of flight, the pressurized gas cylinder 3 is exposed from the liquid oxygen, at the end of the flight, the residual gas in the pressurized gas cylinder 3 is smaller and the utilization rate of medium is improved. After the pressurized gas flows out of the cylinder, the enthalpy value of the pressurized gas is increased by making full use of the heat exchange of pipelines, aerodynamic heating and the heat exchange betweenthe gas and fuel in the storage tank. The parallel redundant design of a pressurization solenoid valve can improve the work reliability and fault tolerance ability of the system. The pressurization system avoids the coupling with an engine, omits a heat exchanger of the engine, and saves the development cost, and at the same time, the pressurization system can be self-verified and improves the accuracy of the pressurization design.