The study aims to characterize the demographic structure of the vegetation of the protected forest Baban Rafi located in the department Madarounfa 50 km south of Maradi. The data were collected based on a forest inventory in 105 plots of 1000 m² installed on 17 transects varying in length from 1 to 5 km. Data analysis has established the list of plants, species diversity, the horizontal structure, vertical structure, and regeneration of woody plants. A total of 52 woody species distributed in 40 genera and 21 families were inventoried. The best-represented families are respectively the Combretaceae and Fabaceae-Mimosoideae. The most important species are Guiera senegalensis, Combretum micranthum, and Combretum nigricans. The average density of woody species (994.86 ± 343.71 individuals / ha) and that of regeneration (17,092.95 ± 10,431.80 seedlings / ha) indicate a good regeneration capacity of the forest. The values of the index of Shannon and evenness Pielou are 3.8 bits and 0.68 bits respectively. The diameter structures of the woody stand and those of the dominant species show a concentration of young individuals of the class from 5 to 10 m. Those in height show a predominance of individuals of heights between 1 and 5 m. These results provide additional information on the current state of woody stands in the Baban Rafi forest and can be used in biodiversity conservation and the management of protected forests in Niger.