Abstract: Based on the data of the comprehensive survey of the Tongbiguan Nature Reserve by Southwest Forestry College from 1995 to 1999,this paper has mainly researched the features of biodiversity.The Simpson index,Shannon-Wiener index and Pielou index are used in α-diversity,while the Whittaker index is used in β-diversity.The results have showed that the reserve is rich in α-diversity as well as in β-diversity.There are 3 475 species of seed plants,belonging to 1 229 genera and 214 families in Tongbiguan.In its floristic composition,858 genera,73.32% of the total genera are tropical distribution.So the forest is one part of the tropical flora.This area is the refuge for many plants during Quaternary ice age.Thus,its component is very complex with a lot of rare and endangered species in it,including 58 species at national level and 52 species at provincial level.The threats to biodiversity were caused by unreasonable human activities including deforestation,logging,forest fire,and unmanaged tourism.Some countermeasures are suggested for dealing with the human threats.