A series of the Pt-Sn/SBA-15 catalysts were prepared and their properties characterized by using X-ray powder diffraction (XRD), N-2 adsorption-desorption, high resolution transmission electron microscope, X-ray photoelectron spectroscopy (XPS) and H-2-temperature programmed reduction. Their performances in long chain alkane dehydrogenation were evaluated in a fixed-bed microreactor with dodecane as a model alkane. The results indicated that SBA-15 maintained the well-order mesoporous structure during the reaction. The performance of the catalyst was found not dominated by its textural properties, but by the molar ratio of Sn to Pt which governed the degree of Sn reduction. Owing to the highest degree of Sn reduction, 1% (by mass) Pt-1.8% (by mass) Sn/SBA-15 showed the best catalytic activity. At 0.1 MPa and 470 degrees C, the molar ratio of hydrogen to alkane at 4, and liquid hourly space velocity (LHSV) 20 h(-1), the dodecane conversion is 10%, and the dodecene selectivity is about 70%.