By employing the P-wave first motion data of 140 stations including Pg phase of 11 stations,Pn of 75 stations and far field P-wave data of 54 stations,we get the focal mechanism of Kangding earthquake with grid search method. The result shows that the earthquake belongs to strike slip type which is identical with the fracture characteristics of Xianshuihe Fault zone. Projecting the onsets we use to the focal sphere of other institutions and calculating the corresponding ration of inconsistent signs,it is observed that our result is most suitable with the observation. And the analysis of aftershock distribution,intensity distribution and tectonic stress field are consistent with the focal mechanism we get.