Abstract: Kaiyuan and Mengzi District is the largest dam area and wetland in south of Yunnan Province in the history, which contains mainly 5 towns and its area reaches 634 km2 (including 300 km2 wetland area). In 1930s and 1940s, the reclaim and cultivate in Kaiyuan and Mengzi district was an important event in Yunnan Province and even in China, which lasted for 13 years. Construction and development in reclamation area had an important influence not only on politics, society and economy at that time, but also a profound influence on later economic development and ecological transition. The event passed more than 70 years, and the overall perspective is not clear affected by era alternation and traditional consciousness. The authors systematically consult and study the related historical materials through investigation, gathering materials and interviews for one year, and research the development problems base on detailed understanding and serious analyzing of these materials to provide evidence for the scientific development in this district.