In this paper, the fractal characterization of the sealing surface topography of metallic gaskets was studied. The influence of the compressive stress on the fractal parameters was also investigated. It’s found that the sealing surface of metallic gaskets is fractal, and its topography can be characterized by the fractal dimension and the scale coefficient. The leakage model of metallic gaskets was established. The research results indicate that the larger the fractal dimension is, and the less the scale coefficient and the non-contact area are, the better the sealing performance of metallic gaskets is.