Ivorian forest rehabilitation policy was long time focused on exotic species plantations. Hence, few studies have concerned biodiversity assessment through naturally restauration. This study aimed to assess plant species diversity in habitats reserved for natural regeneration on a hydroelectric dam in the south-western of Côte d’Ivoire. Botanical inventories were carried out in six habitat types where none human activity has been authorized in the last eight years: lowlands, old cocoa and rubber farms, secondary forests, gallery forests and young fallow. Adult, saplings and seedling trees were counted and their diameters at breast height were measured in plot with 625 m2 based on in each habitat type. Species diversity, structural parameters, and conservation value were compared between these habitats. 364 plants species were surveyed in all the habitats. Among them, 48 are rare, endemic, and/or threatened. The diversity of these species decreased from secondary forests to lowlands. The gallery forests, old plantations and young fallows had the same diversity level. Stem density decreased from secondary forests (277.7 stems/ha) to young fallows (150 stems/ha). Above-ground biomass was higher in the gallery forest. The current reconstitution trends of the plant diversity in these protected habitats shown that this method must be promoted for forest restauration.