Based on the fractal geometry theory，the fractal characterization of metallic gasket seal surface topography was studied.The profiles of metallic gasket seal surface under various compressive stresses were measured by using the stylus profilometer.The fractal dimension，scale coefficient and characteristic length scale of surface profiles were calculated by the structure function method.The influence of the compressive stress on the fractal parameters was also analyzed.The fractal parameters to characterize metallic gasket seal surface topography under various compressive stresses were investigated.It was found that the metallic gasket seal surface is fractal，and fractal dimension and scale coefficient could be used to characterize metallic gasket seal surface topography under various compressive stresses.The formulae that described the relationship between fractal parameters and compressive stress of the different samples were obtained by the regression analysis of the test results.These formulae can be used in the evaluation of the sealing behavior of metallic gaskets.