The high pressure selfsealing flange structure was studied,and the calculation formula of its seal pressure and bolt load was derived and verified by the finite element method.It is found that the relationship between the sealing pressure and the internal pressure is in a linear gradient.The narrower the sealing surface,the stronger the selfsealing effect.The larger the gap between the flange end face and the T-gasket support surface,the larger the initial seal pressure.The structural and thermalstructural coupling analysis of a selfsealing flange was also carried out to study the effects of internal pressure,temperature and bending moment.The results show that high temperature has different effects on the sealing performance of selfsealing flange under high pressure and low pressure conditions.The temperature rise will increase the sealing pressure at low pressure,and will reduce the sealing pressure at high pressure.The stress on the sealing surface of the pressureapplied side gasket of the flange is first decreased with the increase of bending moment,but when the bending moment increases to a certain value,the stress is increased with the increase of the bending moment.