Mesoporous alumina with concentrated pore size distribution was prepared via modification of commercial pseudo-boehmite by adding sodium dodecyl sulfate as the surfactant, and the preparation condition was investigated. The catalyst samples were characterized by XRD,TG-DTA and N_2 adsorptiondesorption. The analysis results indicated that alumina synthesized under acidic condition (pH=1) had concentrated mesoporous pore size (3-6) nm.