The　Pt3Sn/C　catalyst　with　high　electrochemical　activity　was　synthesized　under　optimizing　preparation　conditions.　The　surface　of　carbon　support　pretreated　by　strong　acid　contains　many　O-H　and　C=O　groups,　which　will　increase　the　active　sites　of　PtSn/C　catalysts.　The　catalyst　structure　was　characterized　by　X-ray　diffraction　(XRD),　transmission　electron　microscope　(TEM)　and　temperature　programmed　reduction　(TPR).　The　co-reduction　of　Pt4+　and　Sn2+　ions　causes　Sn　to　enter　Pt　crystal　lattice　to　form　PtSn　alloy　whose　surface,　however,　contains　tin　oxides　with　Sn4+　and　Sn2+　valences,　which　can　promote　the　ethanol　oxidation.　The　crystallinity　of　PtSn　decreases　with　the　reduction　of　the　atomic　ratio　of　Pt:Sn.　By　prolonging　the　reaction　time　of　formic　acid,　the　forward　anodic　peak　current　of　ethanol　oxidation　reaches　16.2　mA　on　the　Pt3Sn/C　catalyst　with　0.025　mg　Pt　loading.　(C)　2007　Elsevier　Ltd.　All　rights　reserved.