NOVELTY - Selenium, copper, indium and gallium are mixed uniformly, and milled to obtain copper-indium-gallium-selenium nanoparticles. Obtained nanoparticles are added to mixed solution of dispersant and film-forming agent, and dispersed to obtain copper-indium-gallium-selenium precursor slurry. The precursor slurry coating is coated on substrate, and to obtain copper-indium-gallium-selenium precursor film. The obtained precursor film is heated, and temperature is increased and maintained to obtain copper-indium-gallium-selenium solar battery light absorption layer thin film.    USE - Manufacture of copper-indium-gallium-selenium solar battery light absorption layer thin film.    ADVANTAGE - The method efficiently provides copper-indium-gallium-selenium solar battery light absorption layer thin film having excellent productivity by simple method.    DETAILED DESCRIPTION - Selenium, copper, indium and gallium are mixed uniformly, and milled to the grain size of 10-10000 nm to obtain copper-indium-gallium-selenium nanoparticles, such that molar ratio of selenide, copper, indium and gallium in the nanoparticles is 0.9-1:0-1:0-1:2. Copper-indium-gallium-selenium nanoparticles are added to mixed solution containing dispersant and film-forming agent in the molar ratio of 10-1000:1, and dispersed by stirring or grinding, to obtain uniform and stable copper-indium-gallium-selenium (CIGS) precursor slurry. The dispersant is ethanol, ethylene glycol, methanol, glycol, 2-propanetriol, glycol or water. The film-forming agent is polyurethane, butadiene resin, terpineol, methyl cellulose, ethyl cellulose, cellulose acetate, vinyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyacrylamide, polyoxyethylene ether, polyoxypropylene ether, ethylenediaminetetraacetic acid, polyethylene, polyurethane-modified butadiene fiber, and/or polyurethane-modified cellulose. The obtained precursor slurry coating is coated on a substrate, dried at 50-400 degrees C for 3 seconds to -30 minutes, and dispersant and film-forming agent are removed under air atmosphere to obtain copper-indium-gallium-selenium precursor film. The obtained precursor film is heated at the rate of 1-120 degrees C/second under inert atmosphere, and the temperature is increased to 200-1000 degrees C. The temperature is maintained for 3-300 minutes to obtain copper-indium-gallium-selenium solar battery light absorption layer thin film. The inert atmosphere is atmosphere containing nitrogen or argon gas.