Abstract: Manned spacecraft has stringent requirements on sealing performance, and the leakage characteristics of the sealing structure are affected by temperature.In this paper, a leakage mode of a silicone rubber seal structure is studied.The gas permeability of rubber at low temperature is tested, and the results show that when the temperature drops from 50℃ to 5℃,the gas permeability decreases by an order of magnitude.The stress-strain relationship and shrinkage characteristics of the material at low temperature are tested, the finite element model of sealing structure is established by ABAQUS,the variation of seal stress at low temperature is obtained, and the results of interface leakage are obtained.At low temperatures, the leakage at the interface of the sealing structure increases slightly.The quantified data of gas permeability and interface leakage of the rubber seal structure at low temperature can be used for reliability assessment.The research findings can provide some references to similar seal design for manned spacecraft.