The southwest part of Yunnan Province is located in the northeast of Indian plate and Eurasian plate，southeast edge of the Qinghai-Tibetan Plateau，which is one of the strongest tectonic activity areas in China. The Longling and Lancang-Gengma earthquakes are typical double-earthquakes in this area. Based on Okada's elastic half-space model and medium wave velocity model of lithology，we calculated Coulomb stress changes of two between double earthquakes and aftershocks. Meanwhile，we analyzed the seismicity of this area. The results showed that: (1)The Longling earthquakes were conjugate and Lancang-Gengma earthquakes were opposite；they were the affecting type. Due to this result，which made the Gengma earthquake in the area with ΔCFS＞0，and the value is 0.35bar. (2)With double earthquakes triggering subsequent aftershocks，because of the Coulomb stress changes of Longling double earthquakes，which triggered most of all aftershocks. The trigger effect was far greater than Lancang-Gengma earthquakes. (3)Based on the viscoelastic relaxation effects after earthquakes，we concluded that the seismic hazard will be higher in the NW—Tengchong-Longling，Yongde-Mengsheng and the southeast of Lancang，the NE—Ruili，Zhenan，Dali and Yongping areas，which is consistent with the distribution of seismic activity.