The invention provides a stretching polypropylene film and its preparation method. The film comprises a co-extrusion compounding base layer and a hot binding function layer, wherein the function layer comprises a component (A), or a component (B), or a mixture of the component (A) and the component (B); the component (A) is an ethylene copolymer having a polar group; the component (B) is selected from an ethylene-butylene copolymer, an ethylene-hexene copolymer, an ethylene-octene copolymer, and a mixture of the above copolymers; the ratio of the vertical elongation rate to the transverse elongation rate of the bidirectional stretching polypropylene film is less than 2; and the surface tension of the function layer of the film is in a range of 36-48dyne/cm. The invention also provides a use of the film in the preparation of film coated paper through the heating compounding with paper, and the film coated paper containing the film.