The present invention relates to a film for a tire inner liner including: a base film layer including polyamide-based resin and a copolymer including a polyamide-based segment and a polyether-based segment; and an adhesive layer including a resorcinol-formalin-latex (RFL)-based adhesive, wherein there is little difference between properties in an MD (machine direction) and a TD (transverse direction), and a method for preparing a film for a tire inner liner, including melting the polyamide-based resin and the copolymer at 230 to 300° C., extruding the molten substance under specific die gap conditions to form a base film, and forming an adhesive layer including a resorcinol-formalin-latex (RFL)-based adhesive on the base film.