Abstract: On April 14, 2010, the Yushu MS7.1 earthquake occurred in Qinghai Province, China. Based on five sets of source parameters published by three institutions at home and abroad, we calculated Coulomb failure stress (CFS) change induced by Yushu earthquake occurrence, and studied the influence of different source parameters on the calculated CFS change and its statistic relation with aftershocks. The result shows that the calculated CFS change patterns are different due to different source parameters, thus the relation between CFS change and aftershock activity is affected. In the source parameters the influence of fault slip angle and dislocation is greater than that of other parameters. In addition, the time length for making aftershock statistical analysis also affects the relation between CFS change and aftershock activity.