The Pt-K/AC, Pt-K/γ-Al2O3, Pt-K/MgO and Pt-K/TiO2 catalysts with were prepared by the impregnation method using AC, γ-Al2O3, MgO and TiO2 as the support, respectively, and H2PtCl6 as the precursor. Catalytic performance of the catalysts for preparing o-phenylphenol(OPP) form cyclohexanone dimers dehydrogenation was evaluated in a fixed bed reactor. These catalysts were characterized by X-ray diffraction , X-ray photoelectron spectroscopy , H2 temperature programmed desorption and CO2 temperature programmed desorption. The results showed that the Pt content, basicity and adsorption of hydrogen of the Pt catalysts were influenced by the different supports. Pt-K/γ-Al2O3 had highest surface Pt content (0.41%), and more surface base sites were favorable for the adsorption of hydrogen and intermediate products and consequently increased the conversion of dimers and the selectivity for OPP. The conversion of the dimer and the selectivity of OPP was always over 99% and 90% with 0.12 h-1 of LHSV and 33 ml/g.h H2 flow rate at 380 ℃ over Pt-K/γ-Al2O3 catalyst during the pilot scale test of～8,000 h.