The invention relates to the technical field of solar cell back plate, and particularly to a film used for a synergistic type solar cell back plate and a preparation method thereof. The film is 15-150 microns in thickness and comprises the following raw materials in parts by weight: 10-90 parts by weight of polyolefin resin, 10-90 parts by weight of adhesive resin and 5-25 parts by weight of functional master batch; the preparation method of the film comprises the following steps of: mixing a polyolefin resin powder material, an adhesive resin powder material and a functional assistant, and extruding the mixture at 100-250 DEG C by adopting a screw extruder to obtain the functional master batch; mixing the prepared functional master batch with the polyolefin resin and the adhesive resin, and preparing the film at 100-250 DEG C by adopting an extrusion tape casting mode or a blow molding mode. The film disclosed by the invention can absorb ultraviolet lights of 10-400 nm, can convert and utilize optical waves which an existing battery piece cannot convert, can widen a solar spectrum absorption and conversion range, and enables a prepared solar cell component to have high photoelectric conversion efficiency.