UMA forest is among the few forests in the surroundings of Kisangani city, and still reserved as well presenting ecological interests that deserve to be studied and valued. The geostrategic position of the UMA forest (in the Northwest of Maiko Park) made it a priority area and of much attention for the ecological and scientific interests. A study on the floristic diversity of this region (PK 97), specifically on the hill of Babolongo is presented in the present work especially the quantitative analysis concerned the abundance of species and families of the base to the top of the mountain. A total of 1335 plants were identified in three plots, distributed in 160 species belonging to 32 families with a basal area of 83.61 m²/ha. The plot at the foot of the mountain was stood out (or marked down), with 520 against 446 plants in the median and 369 at the top; then 103 species at the foot against 98 species at the top and 94 species in the median. Out of 32 families identified, 31 families were present in the foot and the top, 27 families in the median. The basal area were 35.08 m²/ha, 26.16 m²/ha and 22, 36 m²/ha for respectively the base of the mountain, the median and the top. The plot installed at the foot of the mountain is more abundant and diverse. As the transient part (boundary between the field and the primary forest), the present study confirm the hypothesis of intermediate disturbance predicted by Grime stating that the highest specific species diversity is achieved beneath the disturbance regimes of medium intensity and/or frequency.