Due to its high specific impulse, low toxicity, contamination, safety, and cost, krypton has gradually replaced other propellants as the primary choice for electric thrusters on deep-space exploration and large-orbit transfer missions with long-range, long-duration, and large-thrust requirements. However, due to the cryogenic propellant itself having a low boiling point, controlling the pressure change of krypton cryogenic propellant during the process of long-term cryogenic storage has emerged as one of the most important issues that must be resolved and proven to achieve non-destructive storage of cryogenic propellant. This paper examines the necessity and viability of a cryogenic gas propellant liquefaction storage scheme and quantifies the effectiveness of tank pressure control of the supercooled liquid krypton injection mixing scheme to solve the problem at present. Its purpose is to offer scheme examples for the design of a krypton thruster propellant storage unit and the in-tank pressure control during the long-term application process.