The finite element analysis of GH4169 alloy O-ring for a tank container of spacecraft was carried out by ABAQUS software， and the effects of different compression ratios， sizes， coating factors on the resilience and sealing performance of O-ring were discussed. The results show that the compression ratio is an important factor affecting the resilience characteristics， and the resilience amounts and resilience rates of the O-ring are quite different under different compression ratios. The contact performance such as contact stress is greatly influenced by the O-ring structure sizes （outer diameter， wall thickness）. The coating helps to increase the width of the contact surface， but the contact stress will decrease. Therefore， the selection of the sealing ring needs to comprehensively take the compression， the structure size， the coating and other factors into consideration in the flange sealing design.