In order to solve the problem of leakage from quick opening blind of feed gas filter separator in a high sulfur gas field gas gathering station due to the failure of floating lip rubber seal ring, the sealing structure and principle were analyzed. Through the testing and analysis of rubber material and hardness, the investigation was conducted from the aspects of procurement, installation and process operations. The investigation and analysis results show that the manufacturing defects of the rubber seal ring, the rapid gas decompression caused by operation procedure and the incompatibility of the material with the hydrogen sulfide environment are the reasons for the failure of the floating lip rubber seal ring. Based on the analysis and investigation of the causes, the improvement measures including strict control of acceptance procedures, optimization of process operation and re-selection of rubber material for sealing ring are put forward, providing solutions to the leakage problem of quick opening blind plate seal of the feed gas filter separator.