Abstract: The six meetings of the Conference of the Parties to the Convention on Biological Diversity held in 2002 adopted the goal of “significantly reducing the rate of biodiversity loss worldwide by 2010”, and requested Parties to develop biodiversity assessment indicators and to conduct biodiversity assessment. This paper puts forward five indicators for comprehensive biodiversity assessment, i.e. species richness, diversity of ecosystem types, completeness of vertical stratification of vegetation, endemism, and extent of biological invasions, based on the principles of scientific approach, representativeness, and practicality. Methods for comprehensive biodiversity assessment were established, and a national biodiversity assessment was con-ducted by taking 31 provinces (including municipalities and autonomous regions) as the basic assessment units. Biodiversity of provinces was classified into four grades. Yunnan, Sichuan and Guangxi boast highly rich biodiversity. Guizhou, Hubei, Guangdong, Hunan, Chongqing, Fujian, Tibet, Jiangxi, Zhejiang, Hainan, Gansu, Xinjiang, and Shaanxi boast quite high biodiversity. Henan, Anhui, Shandong, Shanxi, Hebei, and Beijing have moderate biodiversity. Jilin, Inner Mongolia, Shanghai, Liaoning, Ningxia, Qinghai, Jiangsu, Heilongjiang, and Tianjin have poor biodiversity.