Annotation:::: The paper focuses on historical aspects of mountain migration in Yunnan province, and discusses what lessons can be taken from this history. Using the method of documental study, the paper finds that in the middle and later stages of the Qing dynasty, the government introduced the high-yield crops like maize and potato into the mountainous and semi-mountainous areas of Yunnan to address food problems caused by the influx of a large number of migrants. Five to six years after initiating the programme, newcomers still used unsuitable methods to cultivate land, resulting in significant reduction of vegetation, soil erosion, river silting, uncultivated land, and frequent occurrence of natural disasters. Allowing migrants to enter Yunnan was originally aimed at developing mountainous resources and stimulating development of the local economy in ethnic areas, but resulted in deterioration of the eco-environment, agricultural production being affected, and mountainous residents becoming increasingly poor. Those historical lessons must be brought into the present work of migration related to poverty alleviation and ecological protection.