The zone of study is located north of Pointe noire town, in the Department of Kouilou, in Republic of Congo. In order to better understand the floristic richness and chorology of the study site of interest, an analysis on a flora, of the autoecological and phytogeographycal spectra of species was undertaken. This analysis is based on the floristic material from different botanical surveys carried out in 2012, and deposited at the National Herbarium of the Congo (IEC). Over a study area of 202’700 ha investigated through 243 phytosociological plots, a matrix of 580 specific and subspecific taxa, distributed in 386 genus and 119 families, were inventoried. Seven species, of which one for the science, were new for the flora of Republic of Congo. The families of Fabaceae, Poaceae, Rubiaceae, Euphorbiaceae, of Malavaceae and Annonaceae and are the most diversified in species. The ecological spectrum highlights the strong preponderance of the phanerophytes, sarcochores and mesophiles, thereby confirming the dominance of the forest biodiversity compared to grasslands. From a phytogeographical perspective, the preponderance of the base element identified as well as three families and eleven genus of endemic nature integrate the flora within the Guineo-Congolian centre of endemism.