Based on metal gasket leakage model of fractal theory,the contact model of the sealing surface was improved,and the domain extension factor,the total elasticity,the first elastic plasticity,the second elastic plasticity and completely plastic deformation the sealing surface were overall considered.The relation between the contact width of metal Oring seal and the designed compression ratio was analyzed,and the leakage model of metal Oring seal structure was deduced and verified.The results show that the contact width is increased with the increasing of compression rate within a certain range.However,when the compression ratio exceeds a certain value,the Oring collapses,leading to a rapid decrease in contact width.The calculated results of corresponding leakage rate are of the same magnitude as the test results under various compression rates,indicating that the established leakage model is applicable to the prediction of leakage rate of metal Oring sealing structure.