The Kangding MS6.3，MS5.8 earthquakes with two mainshocks occurred in the southern segments of Selaha and Zheduotang of the Xianshuihe fault. The spatial and temporal distribution of mainshocks and aftershocks，the energy release process，and the daily earthquake frequency in 30 days after the first mainshock showed that they were spatial-time segmentations. The seismogenic structures，energy release and surrounding rocks of moderate-strong earthquakes in the Xianshuihe fault since 1962 reveal that most earthquakes in the Xianshuihe fault are of isolated earthquake types and mainshock-aftershock types. Only the 1972 Kangding(Tagong)earthquake and 2014 Kangding earthquake are of the multiple mainshock type，both occurring around the huge Cenozoic granitic mass，called Gongga mountain mass(also called “Zheduoshan granitic mass”)，in the southern of the Xianshuihe fault. The multiple mainshocks of these earthquakes may be caused by the resistance of tough Cenozoic Gongga mass. The moderate earthquakes could not continue propagation in strong mass，and the accumulative energy in sandstone and altered sandstone nearby resulted in the next mainshocks.