Abstract:In order to prevent design failure on sealing of large diameter flange bolts under high pressure,two worth parameters were put forward from the factors relation to the failure on sealing of high pressure flange bolts,which included gasket characteristic and inhomogeneous gasket stresses.New concepts of both characteristic ratio and characteristic factor that reflected gasket general characteristics were analyzed based on gasket factor and pre-tightening unit sealing load.Gasket safety factor was presented to characterize the safety remain of both structure and material characteristic under different calculation pressure.Typical safety factor curve was drawn that safety factor was descends as calculated pressure increased,and there was one inflexion during descending.Gasket applied pressure was greater than the inflexion pressure,and was smaller than the calculated pressure of safety factor was equal to 1.0.The method that uses the pressure calculated for all kinds of gasket at different safety factor to design the gasket sealing can ensure the effectiveness of sealing structure.