The MS6.1 earthquake is foreshock-mainshock-aftershock type which happened in boundary region between Zogang and Markam counties on August 12，2013． Within 9 hours before the main shock seven times more than the ML2． 0 earthquake occurred，in which the maximum magnitude is ML4． 7． In this paper，the earthquake focal mechanism changing process of Zogang-Markam MS6． 1 earthquake sequence is studied by calculating correlation coefficient of body wave spectral amplitudes，and the result shows that the correlation coefficients of spectral amplitude of foreshocks present high value fluctuation，the average value is 0． 86，what shows that the focal mechanism of foreshocks are similar; and the correlation coefficients of spectral amplitude of aftershocks present low value，what shows that the possibility of a large earthquake is not high after time．