Abstract: The Cycas community is certainly a more primitive and ancient vegetation type in tropical and subtropical zones, but so far as inland Eurasia is concerned, it may extend to the boundary of Yunnan and Sichuan province, and make the most northern border line by itself. This paper deals with the natural community characters of Cycas panzhihuaensis which has been remained in moun- tain valley of Dukou City, Close to Jinsha River, at N.latitudes between 26°36′- 26°39′, E. longitudes between 101°33′,--101°35′. With a total area about 310 hectares, this community is dispersed over there, occupying the altitude 1100- 2000 m above sea level. Its habitat is a limestone mountain covered with dry open woodlands, that has resulted under a river valley climate with long dry and hot seasons (Nov.-May), spreading largely to the repeated firing, gra- zing, and shifting cultivation.

Key words: Valley of Jinsha River