In this paper, the electrodeposited Cu-In-Ga metallic precursors have been sulpho-selenized by using H2S gas as the sulfur source and Se vapor as selenium source. Through the comparative experiments of selenization, sulfization and sulpho-selenization of the Cu-In-Ga metallic precursor, it has been found that the formations of CuInS2 phase and CuIn(S,Se)2 phase have priority over and restrain the formation of CuInSe2, so that the InSe phase diffuses into the film and weakens the phenomenon of separation into two phases in the film. Then the process of first selenization and sulfization next was made to optimize the preparation of Cu(In,Ga)(S,Se)2 film. At 250 ℃, the pre-selenization temperature, the solar cells with 570 mV open circuit voltage are prepared, while at a higher pre-selenization temperature, the solar cells with a large short-circuit current are prepared. Finally the optimized solar cell with 10.4% efficiency is obtained.