A novel micro/mesoporous composite material Beta-FDU-12 (BF) was successfully synthesized via a nano-assembling method. BF was used as a catalyst support additive mixed with γ-Al₂O₃, when preparing a hydro-upgrading catalyst. The BF micro/mesoporous material and its corresponding catalyst CoMo/BFA were characterized using SAXS, XRD, FTIR, TEM, N₂ adsorption–desorption, pyridine-FTIR, UV-Vis DRS, Raman and XPS techniques. The physicochemical properties of CoMo/BFA were compared to those of the reference catalysts with different support materials including γ-Al₂O₃, FDU-12-γ-Al₂O₃ and ZrFDU-12-γ-Al₂O₃. The characterization results demonstrated that CoMo/BFA showed excellent textural and acidic properties. Furthermore, the addition of EDTA by the post-treatment method improved the dispersion of the active metals. The catalyst CoMoE/BFA exhibited the best hydro-upgrading performance of FCC gasoline (HDS efficiency 94.2% and RON loss 0.8 unit), which could be attributed to the synergistic effects of the open porous structure, excellent textural property, appropriate acidity, and the favorable dispersivity of the active centers.