Abstract: The liquid hydrogen storage tank in a liquid hydrogen plant is taken as the object of study, and a three-zone model is established for calculations by choosing suitable control equations for three zones: liquid hydrogen, gas-liquid phase interface and superheated flash vapor. The simulation of a 10 m³ liquid hydrogen storage tank with a 50% filling rate is carried out from the self-pressurization process to the first venting to the initial pressure. The characteristics of the tank pressure, the mass flow rates of saturated liquid hydrogen and superheated flash vapor, the temperature, and the volume of the liquid hydrogen storage tank are compared with each other for different venting mass flow rates at a specific venting time. The results show that the mass flow rate of superheated flash vapor decreases with the increase of the venting time, the shorter the pressure venting time is, the closer the superheated flash vapor temperature is to the initial temperature after the venting, the mass flow rate of the boiled liquid hydrogen undergoes a significant surge during the venting stage, and the magnitude of the increase decreases with the increase of the venting time.