Abstract: Biodiversity conservation is an important field to international biology research and practice. At present, human factors occupy the dominant position to count the biodiversity value, which could not exactly reflect the actual value of biological diversity. In this paper, three assessing methods for species diversity conservation of forest ecosystem were studied, and data of the 7th forest resources inventory from Yunnan Province was analyzed to verify the methods. The results showed that the method with ShannonWiener index adding endangered index and endemic species index to amend could scientifically reflect the reasonable conservation value of species diversity. The final approach reflected three most important aspects of objective existence of the biological diversity. It could avoid the influence to assessing results owing to human factors, but also reflect the science and rationality of assessment, help to further strengthen the protection and rational utilization of biological diversity.