n analysis to natural environment of China suggested that HU population line,whichlink up Tengchong and Heihe, is an important ecological boundary in China, the physical-based of the analysis are distributions of vegetable-soil system,natural disasters and climato-logical charateristics, the change of these distribution was been result to geomorphologicalregional change; in other words, the area near HU line is a ecological sensitive zone. Withphysical-geographical analysis,the sensitive zone is divided to ...