Abstract: Cathaya argyrophylla is a famous Tertiary relic species and endemic in China. In recent years, it was discovered at the area of the northern part of Yuecheng Ling--the southwest of Hunan (locating in N, 26˚33′ and E. 110˚36′ at an altitude of 950--1050m.)and may be regarded as a news to the province. The mixed forest grows on the top of a cliff which is surrounded by a lot of the higher mountains at alt. 900--1500m. The area is isolated from human disturbance. So it can be survived to date. The compositions and the flora, the layers, the life form, the leaf size class and leaf texture are studied. The result shows that most life form are the chamaephyta and the microphyll with coriaceous texture. According the abundance, dominance and the frequence of the Stands the importance value index are calculated. Basis on the tree analysis of Cathaya the growth curve is given. The related communities in this area are also described.Some problems such as the reasons why Cathaya in this area can be survived, and why the cliff is the common habitat of all Cathaya forests everywhere, and the differences between Cathaya-Tsuga mixed forest in this area and the others are discussed.