After the establishment of the biodiversity conservation area of the Soubré hydroelectric dam, scientific studies showing its value as a biodiversity reserve and its importance for the population were not implemented. As a result, no sustainable management strategy has been initiated. this study was conducted to make up for this shortcoming. It likes to assess its conservation value. The data collection methodology combined botanical inventories and an ethnobotanical survey. The analysis of data was based on the plant diversity and the importance of the area for local populations. Investigations show a rich flora of 346 species. There are 38 endemic species, 10 vulnerable and 8 locally threatened with extinction. This flora richness allows to attribute to the conservation area the High Conservation Value of category 1 (HCV 1). Among the species list, 84 are cited by the populations as useful plants. The use categories are, in order of importance, medicinal use, food use, Handicrafted use, timber. The organs sought are mainly the leaves in the practice of traditional medicine, the fruits in food and the stem in crafts, timber and firewood. Among useful species, 13 are very important for local population. Of these, 6 are less abundant in the area such as Ricinodendron heudelotii, Carpolobia lutea G. Don. The capacity for the area to serve as a refuge for useful species gives it the HCV 5. These results will allow the implementation of appropriate management.