The leakage characteristics of planar solid oxide fuel cell (SOFC) compressive seals were studied quantitatively.In order to simulate the complex morphology of the rough leaky channel,a rough surface numerical reconstruction technique was used to construct different gas leak channels.By considering the minute size and complex boundaries,the gas flow characteristics were numerically analyzed by using the Lattice Boltzmann method (LBM),and the leakage rate calculation model including the geometric parameters of the rough surface was established.Based on the microcontact mechanics analysis of single rough peak,the quantitative relationship between structural characteristic parameters of leakage passage and stress was established,and the effects of various factors on sealing tightness were analyzed.The results show that the main influencing factors of compressive seal structure are rough surface morphology,mechanical properties of sealing material,physical properties of sealing fluid and working state of sealing structure.The leakage rate will decrease with increasing temperature and surface roughness.The material has slight deformation in the process of compression sealing,which ghas small influence on leakage rate.The difference of thermophysical properties of different media will lead to the difference of leakage rate.The model was applied to the leakage rate prediction of a SOFC seal structure.The calculated results are in good agreement with the experimental results,which proves the accuracy of the model.