Four earthquakes with M_S7.0 in Jiuzhaigou, Sichuan, M_S6.6 in Jinghe County, Boltara Prefecture, Xinjiang, M_S5.4 in Qingchuan County, Guangyuan City, Sichuan, and M_S4.8 in Rongchang District, Chongqing, were selected as case studies. We draw the line charts of the four earthquake disaster indices(the number of active WiFi, the number of wireless network networking equipment, the number of online equipment, the number of active stations) before and after the occurrence of earthquake to show their changes in number. the availability of earthquake disaster index is verified by comparing it with that of the previous day, and the effective index is selected, which is convenient for further research on the rapid acquisition of the location of the extreme earthquake area and the direction of the influence field after the earthquake.