The invention relates to the technical field of membrane and discloses a method for preparing a zwitterion membrane by use of alkaline anion exchange membrane solution and acid cation exchange membrane solution. The acid cation exchange membrane solution is prepared from polyving alcohol (PVA) and polysilicon copolymer containing -COOH group or acid-type sulfonated polyphenylene oxide containing -SO3 group; the alkaline anion exchange membrane solution is prepared from PVA, alkaline ammonium polyphenylene oxide containing -N+(CH3)3OH- group and micromolecule alkoxyl silane crosslinking agent. The acid cation exchange membrane solution and the alkaline anion exchange membrane solution are blended through pre-sol-gel reaction, so that the acid group (-COOH or -SO3) can be combined with the alkaline group (-N+(CH3)3OH-) to form an ion pair, and a self-assembly structure is formed through combination of ionic bonds, therefore, the zwitterion membrane has a closely-connected ion pair structure and the stability and the separating property of the membrane can be improved.