The invention discloses a PVB (polyvinyl butyral) film for dynamically rejecting infrared rays and resisting ultraviolet rays and a preparation method thereof. The functional PVB film comprises cesium tungsten bronze, antimony indium oxide, indium tin oxide, titanium dioxide, nano carbon spheres, zirconium carbide, PVB resin powder, a plasticizer, a trace improver and the like. The preparation method comprises the following steps: dispersing the cesium tungsten bronze composite nanoparticles with a solvent, adding the plasticizer, stirring uniformly, adding the PVB resin powder and trace improver, thoroughly mixing, and carrying out film formation on the mixture by running to obtain the heat-insulation ultraviolet-resistant PVB film. The ultraviolet rejection ratio of the PVB film is greater than 99.0%, the visible light transmittance is adjustable within the range of 60-85%, and the infrared rejection ratio is up to 80-99%; and the PVB film can be directly used for producing heat-insulation infrared / ultraviolet-resistant safety laminated glass, can be widely used in architectural curtain walls, doors / windows, zeniths, automobile windshields and the like, and is a novel energy-saving film material.