Based on the investigation results of Kerria yunnanensis Ou et Hong natural distribution areas in southwest and southeast of Yunnan Province and the related literatures, the role of ecological factors on geographic distribution of K. yunnanensis was reviewed and analyzed. The results show that K. yunnanensis might originate from South Asia in Indian Ocean areas. Naturally, K. yunnanensis is distributed mainly on half slopes of valley straits of Nujiang River and its subsidiary currents, Lancangjiang River and its subsidiary currents, Honghe River and its subsidiary currents, and Irrawaddy River subsidiary currents. The combination of temperature and relative humidity is identified as the principal factor limiting geographic distribution of K. yunnanensis, which is also related with the distribution of its host plants. The unique river valley topography, mountain range alignment, and local weather characteristics in Yunnan Province determine the geographic distribution pattern of K. yunnanensis.