This invention discloses a polymer compound membrane and its preparation method, in which, the method includes: mixing strengthening bodies of a matrix film and inorganic nm materials in an organic solvent to get a uniform slurry to be coated on both sides of a non-woven cloth to get a polymer compound membrane, in which, said strengthening bodies are selected from the following three: 1, an organic monomer and its related initiator, 2, two or more than two polymers, 3, organic monomers and their related initiators and two or more than two polymers, 4, organic monomers and two or more than two polymers.