The real contact state between the end faces in friction pair of mechanical seals was studied with fractal theoryA fractal model for the end face contact of friction pair was proposed，with which the mathematical expressions for the area distribution of micro-contacting points of the friction pair，the micro-contacting area related to the critical elastic and plastic deformations，and the dimensionless fractional contact area were obtained.A corelation curve describing the relationship between the dimensionless contact area and the unit load on the endfaces of GY70 mechanical seal was obtained by numerical calculationResearch results indicated that the real contact area presents an approximately linear increase with surface unit load

and at the same unit load，the real contact area decreases with the increase of characteristic length scale G and increases with the increase of fractal dimension D，but decreases with the increase of D when D is greater than 167.The end-face contact fractal model for friction pair provides a foundation for the study of the friction mechanism and sealing performance of mechanical seals.