The invention provides a preparation method of a nano-particle-based copper indium sulphur selenium film for a solar battery. The method comprises the following steps: depositing a molybdenum metal layer used as a back electrode on one side of a substrate by adopting a magnetron sputtering method, preparing a copper indium sulphur absorbing layer on the molybdenum metal layer used as the back electrode, lining the copper indium sulphur absorbing layer in a selenizing furnace, and performing selenizing treatment so as to obtain a copper indium sulphur selenium absorbing layer; sequentially preparing CdS buffer layer, an intrinsic zinc oxide high-resistance layer, an indium oxide tin film low-impedance layer on the copper indium sulphur selenium absorbing layer so as to obtain the copper indium sulphur selenium film for the solar battery. The preparation method has the following advantages that selected raw materials are safe and environment-friendly, the operating method is simple and convenient, other impurities are not introduced, the conversion efficiency of the solar battery is high, requirements on equipment are low, the energy consumption is less, and the method is environment-friendly and suitable for industrial production.