Abstract: Fall armyworm (FAW) (Spodoptera frugiperda) is an agricultural pest that poses a great threat to China food security. The Northeastern Yunnan is not only the main area for corn planting in Yunnan, but also the main place and corridor for the spread of FAW to China. In 2019, FAW was reported for the first time in Zhaotong, Yunnan, and clarifying the environmental factors that affect its distribution can help implement effective prevention and control in this area. This study conducted a random forest analysis on the occurrence density and environmental factors of FAW in Zhaotong, Yunnan in 2019, and found that the factors which have a greater impact on the distribution of FAW are temperature annual range, precipitation seasonality, temperature seasonality, dryland area and mean temperature of the coldest month. The stepwise regression analysis model shows that temperature annual range and precipitation of wettest month are negatively correlated with the occurrence distribution of FAW; Mean temperature of the warmest month and precipitation of wettest quarter are positively correlated with the occurrence distribution. Dryland area is also an important factor affecting the distribution of FAW. In future research, it is necessary to further analyze the influence of prevention and control measures on the occurrence and distribution of FAW.