Based on the large thrust ring contact method,the friction coupling phenomenon was studied in the course of the interaction of two objects with different materials.The fuzzy clustering analysis method was selected to establish the calculation model,and the relationship between the surface quality similarity of two rub surfaces and the friction coefficient was studied.Experimental results show that the surface quality similarity of two rub surfaces and the friction coefficient is significantly correlated.The friction coefficient is increased with the increasing of surface quality similarity under the same test parameters in dry friction experiment.The Pearson’s correlation coefficient between the calculated surface quality similarity and the friction coefficient is greater than 08,which indicates that the proposed surface quality similarity calculation model is correct.