Based on the investigation of the vegetation and the collection of samples,the species composition and areal type of seed plants in the Luoxu White-lipped Deer Nature Reserve are analyzed. The paper aims to offer the basic data for the management of Luoxu White-lipped Deer Nature Reserve and explore the origin of this flora. The results of the survey show that there are 904 plant species belong to 60 genera and 35 families in Luoxu White-lipped Deer Nature Reserve,in which the genera and families of temperate zone reach 63. 63 % and 89. 17%,respectively. So the flora is of temperate type obviously. On the other hand,the analyses of endemic genera indicate that the flora of seed plants in Luoxu White-lipped Deer Nature Reserve is closely related to Hengduan Mountains. The results of cluster analysis show that the flora of Luoxu White-lipped Deer Nature Reserve is closer to Aba Manzetan Wetland Nature Reserve,and far from Wuxi Yintiaolin Nature Reserve. It is argued that the flora of Luoxu White-lipped Deer Nature Reserve and Aba Manzetan Wetland Nature Reserve are affected by the qualitative change in Tibetan Plateau and the climate change is caused by the qualitative change. The flora of Jiuzhaigou Nature Reserve is affected by the change of Tibetan Plateau, and the special geographical position also is a reason. Gexigou Nature Reserve is also affected by Quaternary Glaciation,and the geomorphological character of Hengduan Mountain also is a reason. Moreover, quaternary Glaciation and modern monsoon maybe bring up the flora of Luoxu, too.