NOVELTY - Sputtering of single target, copper-enriched target and copper-poor target is carried out simultaneously on base electrode by magnetron sputtering method, to form copper-indium-gallium-selenide (CIGS) precursor film. Solid single-substance selenium source is heated to 180-450 degrees C in vacuum at specific air pressure condition, to obtain saturated selenium steam pressure. The CIGS precursor film is placed in saturated selenium steam pressure, and warmed to 450-600 degrees C at rate of 10-100 degrees C/minute for 10-60 minutes, to form light absorption layer of CIGS film solar battery.    USE - Preparation of light absorption layer used for copper-indium-gallium-selenide film solar battery.    ADVANTAGE - The high-quality light absorption layer of solar battery is formed easily, and has excellent photoelectric property, controllability and uniformity.    DETAILED DESCRIPTION - Sputtering of single target, copper-enriched target and copper-poor target is carried out simultaneously on base electrode by magnetron sputtering method, to form copper-indium-gallium-selenide (CIGS) precursor film. Solid single-substance selenium source is heated to 180-450 degrees C in vacuum or inert atmosphere at specific air pressure condition, to obtain saturated selenium steam pressure. The CIGS precursor film is placed in saturated selenium steam pressure, and warmed to 450-600 degrees C at rate of 10-100 degrees C/minute for 10-60 minutes, to form light absorption layer of CIGS film solar battery. The single target material is copper-indium-gallium-selenide (Cu1-x(In,Ga)Se2-x/2, where x is 0.05-0.50). The copper-enriched target comprises copper, copper selenide (CuSe and Cu2Se) and/or copper-indium-gallium-selenide (Cu1-x(In,Ga)Se2-x/2, where x is 0.1-1). The copper-poor target comprises indium-gallium selenide ((In,Ga)4Se3 and (In,Ga)2Se3), and/or copper-indium-gallium selenide (Cu(In,Ga)5Se8, Cu(In,Ga)3Se5, Cu2(In,Ga)4Se7, Cu3(In,Ga)5Se9 and Cu1-x(In,Ga)Se2-x/2, where x is 0.4-1).