Supported platinum group catalyst applied to propane dehydrogenation propylene preparation and preparation method of supported platinum group catalyst

The invention provides a supported platinum group catalyst applied to propane dehydrogenation propylene preparation and a preparation method of the supported platinum group catalyst and relates to propylene. The catalyst is prepared from PtSnN2/N1-Al2O3, wherein N1 is selected from rare earth metals of La and Ce, and N2 is selected from alkali metals of Cs, K and Na. The catalyst is prepared from, by mass, 0.1%-0.5% of Pt, 0.2%-1.0% of Sn, 0.5%-6% of N1, 0.5%-5% of N and the balance Al2O3. The preparation method includes the steps that a cerous nitrate solution or a lanthanum nitrate solution containing the N1 component is added in the preparation process or forming process of an alumina precursor, and a modified carrier of the propane dehydrogenation propylene preparation catalyst is prepared after drying and calcination; Pt and Sn are co-steeped or steeped on the carrier step by step, the catalyst precursor PtSn/N1-Al2O3 is obtained after drying and calcination and then steeped in an N2 component solution, and the catalyst is prepared after drying and calcination.