Annotation:::: The paper focuses on the studies of ecology and rural sustainable development, and aims to identify the trend of sex-ratio evolution during and after the mountain migration in Yunnan province. The author uses documental study and case study to analyse the trend of sex-ratio evolution of the work force in Zhiju village, Yongren county, Yunnan province from 1991 to 2001. According to the findings, the sex ratio of work force in the communities of mountain minorities in Yunnan is unbalanced due to exportation of work force and relocation of local residents. This severely prevents the communities of ethnic minorities in Yunnan’s mountainous areas from sustainable development.
