To prevent the oxidation of copper powder during sintering, SiO2-B2O3 sol was prepared by anhydrous ethanol, tetraethyl orthosilicate and tributyl borate. SiO2-B2O3 sol was used to coat the copper powder which was pretreated by diluted hydrochloric acid. The coated copper powder was used to prepare the paste, then the paste was printed on ceramic substrate and sintered at 600℃.The conductivity of the film was tested by four?probe tester. Scanning electron microscopy ( SEM) was used to observe the surface topograph of copper powder which was coated by SiO2-B2O3 sol, X?ray diffraction(XRD) and thermogravimetric analysis ( TGA) were exploited to characterize the oxidation condition of sintered copper podwers .The results show that when m(SiO2-B2O3):m(Cu)=,copper powders are homogeneously coated with SiO2-B2O3 sol .,the copper film has the highest electrical conductivity, the relative electrical conductivity is 57%;the surface of copper powder has been scarcely oxidized below 700 ℃. Experimental results show that under the suitable coating rate, copper powder has good oxidation resistance and the copper conductive film has good electrical conductivity.