In order to study the influencing factors under the high and low temperature working conditions of the Y-rings under ultra-high pressure in natural gas equipment, PTFE and its four modified materials were selected as sealing materials, and the effect of the lip interference, lip angle and back lip angle on the static sealing performance of the Y-rings was analyzed.The results show that the maximum von Mises stress of the Y-ring decreases with the increase of lip interference, first increases and then decreases with the increase of lip angle and lip back angle.The maximum contact stress of the inner lip increases with the increase of lip interference and lip angle, and first increases and then decreases with the increase of lip back angle.Five parameters,including the width of the Y-ring,substrate height,lip tip height, lip front angle, and lip back angle,were selected,the sensitivity analysis of each parameter was conducted by ISIGHT software.It is found that the width of the sealing ring and the substrate height have the greatest impact on the maximum Mises stress and inner lip contact stress of the Y-ring.The optimal size of the Y-ring was obtained by multi-island genetic algorithm.and the theoretical design result was verified through experiments.