NOVELTY - A copper-indium-gallium-selenium ink preparation method involves preparing a copper-indium-gallium-selenium raw material by crushing copper selenide, indium selenide and gallium selenide, grinding the raw material, and performing centrifugal separation. The obtained product is filtered to obtain 3-20 nm particles and 200-400 nm particles that are added to obtain copper-indium-gallium-selenium particles. Sodium chloride and the copper-indium-gallium-selenium particles are added with water-base solvent, and ultrasonic treatment is performed in an ultrasonic basin to obtain water base ink.    USE - Method for preparing a copper-indium-gallium-selenium ink that is utilized in a tin-selenium solar battery.    ADVANTAGE - The method enables preparing the copper-indium-gallium-selenium ink without chemical solutions, waste generation and expensive vacuum equipment in an environment-friendly, cost-effective and practical manner.    DETAILED DESCRIPTION - A copper-indium-gallium-selenium ink preparation method involves preparing a copper-indium-gallium-selenium raw material by crushing copper selenide, indium selenide, gallium selenide, copper gallium alloy, copper-indium alloy and selenium powder, and grinding the raw material in a wet rolling ball mill at rotation speed of 200-500 rpm and revolution speed of 500-800 rpm. Centrifugal separation is performed at 2000-8000 rpm for 30 seconds to 10 minutes. The obtained product is filtered to obtain particles of 3-20 nm and 200-400 nm. 10% 3-20 nm particles are added with 90% 200-400 nm particles to obtain copper-indium-gallium-selenium particles. Water-base solvent and organic base solvent are prepared. 0.3-3 wt.% sodium chloride and 40-70 wt.% copper-indium-gallium-selenium particles are added with the water-base solvent or organic solvent, and ultrasonic treatment is performed in an ultrasonic basin to obtain water base ink or organic base ink, where the water-base solvent comprises 60-80 wt.% water, 5-15 wt.% polyvinyl alcohol, 4 wt.% ethyl cellulose, 3-10 wt.% polyvinyl acetate and 3-8 wt.% polyethylene glycol, and the organic solvent comprises 50-84 wt.% toluene/oil, 3-8 wt.% ethyl cellulose, 2-8 wt.% benzyl alcohol, 1-10 wt.% polyethylene glycol and 10-35 wt.% terpineol.