To study the contact state and sealing mechanism of real pipeline connectors under tightening torque so as to effectively control the sealing performance of pipelines,the real pipeline connectors were taken as the research object,and the real contact morphology data was measured.A finite element model of rough contact surface was established based on reverse modeling technology,and the relationship between the real contact area ratio and the average contact stress was obtained by using the finite element simulation analysis method.The results indicate that both elastic and plastic deformation occur simultaneously when the displacement load is applied.As the load increases,the area of plastic deformation becomes larger and the part that forms the real contact area gradually increases.Based on the percolation theory,the contact interface was modeled and simulated by grid modeling,and the minimum real contact area ratio required for the contact interface to achieve sealing was obtained by using the path finding algorithm.The minimum contact stress required for the contact surface of pipeline connectors to achieve sealing was obtained by combining the simulation results.The research results provide important sealing evaluation indicators for the simulation analysis of the sealing performance of pipeline connectors,and further provide reference for obtaining the minimum tightening torque of pipeline connectors under sealing conditions through simulation analysis.