The catalytic performances of a series of Cu compounds in the oxidative carbonylation of methanol to dimethyl carbonate (DMC) were investigated by employing the soft-hard acid-base principle, the ion radius rules and the substitution effect. It has been found that it is the most appropriate for the border base Br- to coordinate with a border acid CuII and a soft acid CuI, improving the insertion of CO to the CuII—OCH3 bond, which is the rate-limiting step in DMC synthesis. Among a series of Cu(5-R-phen)Br2 catalysts (R = 5-NH2, 5-CH3, H, 5-Cl or 5-NO2, phen = 1,10-phenanthroline), the methyl substituent with the爓eakly electron-donating爀ffect is the most beneficial to the activation of CO and the insertion of CO to the Cu-OCH3 bond, and Cu(5-CH3-phen)Br2 exhibits the highest activity. For Cu(R?-phen)Br2 (R? = 2-CH3, 4-CH3, 5-CH3, 2,9-dimethyl, 4,7-dimethyl, or 5,6-dimethyl), the activity of the catalyst containing the mono-methyl group is higher than that of the corresponding catalyst with two methyl groups; the steric hinder effect is outstanding with the methyl close to N atoms, and the more the number of the methyl is, the lower the activity of the catalyst is. When Cu(5-CH3-phen)Br2 with the highest activity was used as the catalyst under the conditions of total pressure 4.0 MPa, ratio of partial pressure of CO to O2 19:1, reaction temperature 130 癈 and concentration of the catalyst in methanol of 0.011mol 稬-1, the turnover number and selectivity for DMC were up to 67.2 and 96.9%, respectively.