In order to study the sealing performance of the sealing gasket in the wellhead connector under the complex conditions of high temperature and high pressure on the seabed,the heat transfer model and thermodynamic coupling mathematical model were established according to the heat transfer theory,and the temperature field finite element model of the wellhead connector was established by using ANSYS software.Based on the numerical simulation of temperature field,the steady state and transient thermal structure coupling numerical simulation analysis was carried out to obtain the influence of oil and gas medium pressure and temperature on the sealing performance of wellhead connector.The results show that the higher the temperature of oil and gas medium,the greater the temperature gradient inside the sealing gasket.The temperature difference fluctuation between the parts of the connector and the sealing gasket under the influence of temperature impact is greater than that under constant and instantaneous temperature change.Through the steady-state thermal-structural coupling analysis,it is found that the metal sealing gasket has expansion deformation due to the temperature change,and the deformation is larger than that when no temperature load is applied,which indicates that the temperature load will directly affect the sealing performances of the connector in certain conditions.Through the transient thermal-structure coupling analysis,it is found that the rapid change of temperature in oil and gas medium leads to a larger linear expansion of the contact surface in the sealing gasket than that of the outer gasket,which leads to the discordant deformation inside the sealing gasket.Therefore,excessive temperature rise should be avoided in the actual working environment.