High performance of transparent conductive Cu-based Ga: ZnO (GZO) multilayer thin films deposited on flexible substrates are achieved by two Al2O3 barrier layers and oxygen. The multilayers exhibit high figure of merit (FOM) of 3.03 × 10−2 Ω−1 with the resistivity of 4.24 × 10−5 Ω cm and sheet resistance of 6.06 Ω/sq., while the average optical transmittance is above 84% in the visible range. The FOM value is the highest among all the reported Cu-based transparent conductive thin films. The influence mechanisms of Al2O3 layers and oxygen on structural, morphological, electrical and optical properties of the multilayer films are also investigated. These results indicate that the insertion of two thin Al2O3 barrier layers and the filling of oxygen during the deposition of GZO layers is an effective way to improve the photoelectric performance of the Cu-based GZO multilayer films.