Mesoporous aluminas (MAs) were synthesized in a CTAB-P123 dual-template system and used to prepare Pt-Sn/MAs catalysts by vacuum impregnation method for i-butane dehydrogenation. Characterization results showed that the dose of P123 and CTAB for synthesis of MAs can tune Brunauer-Emmett-Teller surface area, pore size and total acidity. i-Butane conversion has linear relationship with the total acidity of MAs, which also affects the product selectivities. Meanwhile, pore size of MAs cooperatively affects the product distribution via diffusion control. The deactivation of the catalysts is proportional to the coke formation, which improves the dehydrogenation product selectivities during time on stream. [GRAPHICS]