Gynaephora alpherakii (GA) is mainly distributed in the Qinghai-Tibet Plateau of China. As one of the most important insect pests, the occurrence of the GA seriously affects the growth of grass, reducing the grassland production and preventing the development of the animal husbandry. It is vital for monitoring its biological characteristics, occurrence regularity, quantitative changes and main effect factors. However, limited by the field observation,the spatial distribution and inhabitable area were still unclear. The regional distribution (Qilian Mountain National Park in Qinghai Province) was investigated based on UAV aerial photographing technology. The ecological niche was constructed based on the environmental factors (grassland vegetation, soil, climate and topography), combined with field observation and BIOMOD. Based on the above mentioned, the inhabitable area of GA was divided. The results showed that among the all field observation sites, the spatial distribution of prairie caterpillars was heterogeneous, with the number of variations from 1 to 2046 in different observation sites and 0 to 136 in different aerial photographs;the random forest model exhibited the best performance with Kappa, TSS and AUC were 0.6, 0.75 and 0.93, respectively;the inhabitable area of the first-grade to the third-grade was small with 14.68% of study area, and located in mid-eastern of study area, the inhabitable area of the fourth-grade and the fifth-grade was large with 85.32% of study area, mainly located in western of study area. The research result showed that UAV can be potentially used to obtain the basic data for GA distribution modeling, which provided a theoretical and practical basis for further quantitative understanding of the ecological status and help for the early warning and management practices of GA outbreak.