The invention discloses a diffusion and brightness enhancement film and a method for manufacturing the same. The diffusion and brightness enhancement film comprises a diffusion film and a brightness enhancement layer. The brightness enhancement layer is positioned on the diffusion film, the diffusion film comprises one or a plurality of diffusion layers, each diffusion layer comprises a resin base material and light diffusing agents uniformly dispersed in the resin base material, an absolute value of the difference between a refractive index of each light diffusing agent and a refractive index of each resin base material ranges from 0.01 to 0.4, and the brightness enhancement layer comprises a plurality of microstructures which are arranged according to a linear structure or a nonlinear structure. The diffusion and brightness enhancement film and the method have the advantages that the diffusion and brightness enhancement film is manufactured by a novel process, various toxic solvents are omitted, and shortcomings of white stripes, folding, scratching, poor thermal stability and the like of a finished product are overcome; the brightness enhancement layer is compounded on the surface of the corresponding diffusion layer, and working procedures are simple; after the multifunctional optical film is applied to a backlight module, the service quantity of diaphragms can be reduced, and shortcomings of interference, scattering, absorption and the like when various diaphragms are used simultaneously can be overcome; the manufacturing cost of the diffusion and brightness enhancement film is reduced, and the quality of the diffusion and brightness enhancement film is improved.