Abstract：The Coulomb stress change around the source fault induced by the 2008 Wenchuan MW7.9 earthquake is calculated based on the fine coseismic slip distribution model. The reliability of Coulomb stress change and the impact that the strike, dip and rake of receiver fault, the friction coefficient and Skempton coefficient towards the reliability of Coulomb stress change is assessed from the CV (coefficient of variation). The unreliable Coulomb stress change is eliminated according to the threshold value and the relationship between the reliable Coulomb stress change and the distribution of aftershock is analyzed. The results show that the most reliable Coulomb stress change is found inside positive and negative Coulomb stress change area, and the closer to the boundary between positive and negative, the more sharply the reliability decline. Among the parameters analyzed in this paper, the dip angle of receiver fault has the greatest effect on the reliability of Coulomb stress change. 79.3% of aftershocks locate in the distribution area of reliable Coulomb stress change and the aftershock triggering rate decreases by 3.1% after excluding the unreliable Coulomb stress change and aftershocks in unreliable area.