We did a primary research on the stress triggering effect on the mainshock of April 1,2014 MS8.2 earthquake in northern Chile and its strong aftershock of April 3,2014 MS7.6 earthquake by large earthquakes occurrimg on the boundary of south American plate since 2000，and the stress triggering effect on the subsequent aftershocks by the mainshock. The results show that the previous earthquakes are beneficial to the occurrence of the mainshock，and the previous earthquake and the mainshock have triggering effects on the strong aftershock of MS7.6 earthquake. The Coulomb stress change on the two nodal plane of the mainshock's focal mechanism is positive，which was caused by the previous earthquake. Using different friction coefficients，the minimum ratio is 22.2% for the fault segment of the mainshock's rupture plane whose Coulomb stress change exceeds the threshold(0.01MPa). The minimum and maximum ratio of the positive Coulomb stress change fault segments are 74.3% and 95.5% respectively. The Coulomb stress change is positive on the two nodal plane of the April 3,2014 MS7.6 earthquake，which was caused by the previous earthquake and the mainshock，and is considerably larger than the stress triggering threshold. The minimum ratio of the fault segment with Coulomb stress change bigger than threshold is 58.2%，and the minimum ratio of the fault segment with positive Coulomb stress change is 64.0%. 8 aftershocks focal mechanism data was collected from Global CMT catalogue，the Coulomb stress change on each aftershock nodal plane was calculated. The study results show that the mainshock's triggering effect on the aftershock is not obvious，and needs further studing，because the limited data of aftershocks were used in this research.