In order to study the influence of rough surface characteristics on the leakage of the metal seal ring gap, a mathematical model of three-dimensional rough surface was established according to mathematical formulas, a micro rough surface was established with surface roughness as an evaluation index, and a leakage channel model was established after contact calculation using finite element method. , Using CFD technology to simulate and analyze the flow field inside the gap of different structures, get the flow field distribution and velocity distribution, and calculate the leakage rate of the sealing gap. The results show that as the height of the sealing gap decreases, the surface roughness value decreases, and the pressure difference between the inner and outer chambers decreases, the leakage rate of the sealing system gradually decreases.