Direct propane dehydrogenation (PDH) has emerged as one of the most promising approaches to produce propylene. Pt is a commercially used metal for PDH and Sn is the most commonly used promoter for Pt catalysts. The PDH reaction requires the activation of the C-H bond, meaning its kinetics depend on the electronic structure of the Pt. However, the energy levels of the d-states in Pt and Pt-containing alloys, which play a crucial role in directing bond formation, have rarely been directly measured experimentally. We have developed PtSn loaded Al2O3 catalysts with various Pt:Sn ratio, which showed very different propylene formation rate and deactivation rate. Here we apply for the Pt L3 edge RIXS study to measure the d-band of Pt and Pt-C bond strength after H2 activation, propane dehydrogenation and regeneration. Compared with different Pt:Sn ratio will determine the optimal electronic structure of Pt, providing fundamental descriptor in C-H activation.