Diphenyl carbonate (DPC) is a material for the green production of Polycarbonate.Among of non-phosgene methods for the synthesis of DPC, the transesterification between dimethyl carbonate (DMC) and phenol seems to be the most promising and practical candidate for DPC synthesis because DMC is nontoxic to human and environment [7].n-Bu2SnO shows the high activity and the transesterification selectivity in the transesterification of DMC and phenol to DPC, but its activity is not high enough for the industrial purpose.Effect of CuO, Cu2O, CuX (X =Cl, Br and I) and Cu powder on the catalytic activity of n-Bu2SnO were investigated.The results showed that they as promoters could obviously enhance the activity of n-Bu2SnO except for Cu, but the characterizations of XPS and XRD identified that CuO could be reduced to Cu by phenol on the reaction conditions, and Cu2O was stable.When the reaction was carried out between 150 and 180℃, with molar ratio of n-Bu2SnO to Cu2O of 8∶1, catalyst amount 0.0067 (molar ratio to materials), reaction time 10h, molar ratio of dimethyl carbonate to phenol of 3∶1, the conversion of phenol and the transesterification selectivity were 60.3% and 99.2%, respectively.In the transesterification, Cu2O as the basic promoter might strengthen the nucleophilicity of phenol, and formed the acid-base synergistic effect with n-Bu2SnO, resulting in the active enhancement of n-Bu2SnO.