Abstract: There are many factors that affect the characteristics of joint surface, and most of which are nonlinear. A method of classifing the factors is presented in this report, in which the influence of the behaviour of joint surface itself is indicated as characteristic parameters of joint surface. A model of the normal characteristic parameters is developed, meanwhile, a method of separating the parameters from a system and the expression of the parameters re researched. Some application examples are given out as well.

Key words: Characteristic parameters, Joint surface, Model, Separate