The invention relates to the field of liquid crystal display back light modules technique, and particularly relates to a brightening film and a method for its production. The invention provides a brightening film, so as to overcome the defect that an existing brightening film is prone to the Moore effect and the Newton ring. The invention comprises a substrate and a prism structure layer, wherein the prism structure layer is bonded to the base material layer, and the prism structure layer is composed of repeating units including a first prism structure unit and a second prism structural unit; the first prism structure unit is a group of concentric prismatic rays; the second prism structure unit is a group of concentric prismatic rings; the second prism structure unit intersects the first prism structure unit. A group of concentric prismatic rays includes a number of prismatic rays. A group of concentric prismatic rings includes a number of prismatic rings. The invention can improve the brightness gain and have the anti-interference effect, and can reduce the Newton ring phenomenon and the Moore effect.