Plastic packaging films are not recyclable, difficult to degrade and thus threaten the environment and the health of humans and other animals. Therefore, the purpose of the research is to derive edible polysaccharide films from Highland barley bran fermented by Aureobasidium pullulans. Fermentation conditions using UV-mutated A. pullulans were optimized and the rheological, mechanical and barrier properties of edible polysaccharide films were analyzed. The polysaccharides produced by mutagenesis increased by 8.6% after fermentation. The products before and after fermentation contained α- and β-glycosidic bonds, C-O-C, C=O, O-H, and other characteristic peaks of polysaccharides. Post-fermented polysaccharide films (post-FPF) were more moisture resistant than pre-fermented polysaccharide (pre-FPF) and control group (CGPF). Mechanical properties were better for CGPF than post-FPF, but post-FPF had good water solubility. It was feasible to make an edible polysaccharide film with improved water solubility. Post-fermentation polysaccharide films could help to reduce the cost of edible film production and improve the comprehensive utilization of bran.