The contact between two rough surfaces is essentially the contact of a large number of asperities，which leads to a challenging scientific problem due to the complexity of interface behaviors. In this paper，the contact of an asperity and the asperity interactions are considered. The downward displacement of mean of asperity heights is used to represent the effects of the asperity interactions. The normal contact model can then be established by the summation integral based on fractal theory. Once the normal preload is given，the probability density function of truncated asperity contact area can be determined. Then the tangential load-displacement model of joint interface can be established by Mindlin theory，Masing’s hypothesis and fractal theory. The effect of different parameters on energy dissipation is studied by numerical simulation. The results show that the energy dissipation decreases with the fractal dimension D decreases，or with the fractal roughness parameter G increases. This means that the energy dissipation is lower when the rough surface is coarser. The energy dissipation will decrease with the normal preload increases.