The regional tectonic background and characteristics of active faults of the Yutian MS 7. 3 earthquake on February 12，2014 are discussed in the paper． After the analysis of the epicenter of the MS 7. 3 earthquake in 2014 and focal mechanism of former strong earthquakes around it，the authors deduced that the seismogenic fault of the MS 7. 3 earthquake is the east branch of the Ashikule fault． The MS7. 3 earthquake in 2014 and the MS7. 3 earthquake in 2008 are two strong earthquake events on the different section of the Ashikule fault，where the fault behavior changes from the sinistral slip to normal because of the extensional tail effects in the southern end of the Altyn tagh fault． It is concluded that the two MS7. 3 earthquakes have the same dynamic source，and the MS7. 3 earthquake in 2008 promotes the occurrence of the MS 7. 3 earthquake in 2014． Finally，the authors calculate the coulomb stress change to seismogenic fault of the MS7. 3 in 2014 from the MS7. 3 earthquake in 2008 using the layered crust model． The result also shows that the MS 7. 3 earthquake in 2008 accelerated the occurrence of the MS 7. 3 earthquake in 2014．