In this paper, the electrodeposited Cu-In-Ga metallic precursors have been selenized by using plasma activation Se source. The power of plasma has great influence on the grain growth of Cu(In1-xGax)Se2(CIGS). The films were shown to be single phase Cu(In0.7Ga0.3)Se2 when the plasma power was 75W. And the fact that high activity Se promotes the generation of binary selenide phase at a low temperature, thus helping the growth of single phase Cu(In0.7Ga0.3)Se2, was proved by XRD analysis of the films selenized at defferent temperatures and the comparison with the films prepared by ordinary selenization. Solar cells have been prepared and found that the single phase have no influence on battery performance. The efficiency can reach 9.4% by process optimization.