A method for preparing a chitosan complex film comprises: (1) reacting polyvinyl alcohol-124 with butanedioic anhydride to obtain a modified polyvinyl alcohol； (2) formulating the modified polyvinyl alcohol-124 into a 0.4 wt % aqueous solution, then adding the aqueous solution containing 0.4 wt % of modified polyvinyl alcohol-124 dropwise into an acetic acid solution at a concentration of 0.4 wt % chitosan to obtain a mixed solution； (3) adjusting the pH value of the mixed solution with a 0.01 wt % NaOH solution to pH 5.5, and removing surface bubbles after standing for one hour to obtain a casting solution； (4) pouring the casting solution into a culture dish, placing the culture dish into an oven at 60° C. and drying to a constant weight to obtain the chitosan complex film. The materials used in the method are inexpensive, and the reaction is not complicated, so the cost of the product is not high.
