The O-ring in gas meter was taken as the research object,the long-acting sealing performance of the O-ring in the rotating dynamic sealing system was studied.Based on the sealing mechanism and characteristics of the rotating dynamic sealing system,the failure mechanism of O-ring was analyzed.By determining the time and speed as the main influencing factors of the long-term sealing performance,and using the compression permanent deformation as the quantitative evaluation index of sealing performance,the prediction model was obtained by quadratic polynomial regression analysis and verified by experiment.The results show that the O-ring has reliable long-term sealing performance.The effect of service time and rotating speed on compression permanent deformation of O-ring is significant,while the effect of service time is greater than that of rotating speed.When the rotating speed is constant,the longer the service time is,the more obvious the compression permanent deformation is.The prediction model can predict the rotating sealing performance of the gas meter under different conditions,which can be used in engineering practice.