Abstract: In the present paper, the species composition, historical cause of formation and floristic characteristics of precious rare and endemic plants in Qinliag mountains as well as the relationship between them and those in adjacent regions have been discussed.1. Qinling being a dividing line between south and north flora of China has 66 species of precious rare plants (PRP) and 169 species of endemic ones (EP).2. The PRP in Qinling have an ancient origin and close historical relationship with subtropical flora in Central China, but the EP in this region show obvious temperate nature and tremendous diversifications and most of them are recently formed neo-endemic species.3. The position of Qinling as the north limit of distribution of subtropical flora in China and the characteristics of PRP in the region were determined by the historical and present divergence of geological and climatic conditions between south and north of the mountains, and the complexity of different topographical and climatic conditions as well as the changes of vertical climatic zones caused by the neo-tectonic movement resulted in the tremendous variations of plants and the formation of many neo-endemic species in Qinling.4. The PRP in Qinling were composed of many floristic elements which have extensive relationship with adjacent regions, especially with East Sichuan-West Hubei (ES-WH) region where many endemic and relic plants of China concentratedly distributed. We suppose that there is a main migrating and dispersing route between the floras of Qinling and subtropical Central China from ES-WH region through east part of Daba mountains to the middle part of Qinling and then to its west part.