Guizhou Province is a typical karst mountainous area,accounting for 61.96% of the total exposed karst area in China.The rocky desertification in the region is serious,the ecological environment is fragile,and the biological diversity is especially vulnerable.Based on biological diversity,this paper established a comprehensive assessment index system of biological diversity using five indices of species richness,diversity of ecosystem types,completeness of the vertical stratification,species endemism,and number of invasive species.Using the established system,we evaluated the biological diversity of each county( districts,cities)for the entire Guizhou Province.The overall results were reported in four grades: excellent,good,average,and poor.There were 10 counties rated as excellent,accounting for 11.36% ; 29 counties as good,accounting for 32.96%; 39 counties as average,accounting for 44.32%;and 10 counties as poor,accounting for 11.36%.The regions with better grades are in remote mountain areas in northeast and southeast of the province,while the areas with lower grades mainly lies in flat terrain in central province.