To verify the technical scheme of cryogenic helium pressurization in the fuel tank of liquid oxygen (LOX)-kerosene rocket, a test device was established and the ground simulation test was conducted. The influences of different pressurization methods on pressure control stability, ullage temperature distribution in tank, helium consumption, gas-liquid mixture, and liquid freezing of pressurized drainage process were investigated. The pressurization method specifically includes pressurization outlet position, diffuser form, and pressurant flow rate. The results show that when pressurized from the liquid zone, the heat exchange of pressurized gas is more sufficient, which reduced the gas consumption by 33.1% compared with that in the ullage zone. However, the stability of pressure control is less satisfying. The form of diffuser has little influence on the gas consumption and the temperature distribution of ullage. The helium consumption for pressurization at a small flow rate is less than that at a high flow rate. For example, when the drainage flow is 10 L/s, the helium consumption can be reduced by 20% compared with that at 40 L/s. Under all experimental conditions, neither ice due to local supercooling in the tank nor bubbles in the drainage pipeline are observed. The test results verify the feasibility of the proposed scheme, and provide a reference for structural design and working condition regulation of the cryogenic helium pressurization system in rocket.