Modified polyvinyl alcohol copolymer and preparation thereof as well as gel polymer electrolyte

The invention particularly discloses a modified polyvinyl alcohol copolymer and a preparation method thereof, and gel polymer electrolyte containing the modified polyvinyl alcohol copolymer. The preparation method of the modified polyvinyl alcohol copolymer comprises the following steps: weighing a polyvinyl alcohol solid; adding water and swelling; after raising the temperature and dissolving, heating in a water bath at 40 DEG C to 45 DEG C; introducing argon gas and adding N-vinylpyrrolidone and a functional monomer; and after uniformly stirring, adding an acidic cerium ion solution and reacting for 3h to 5h to prepare the modified polyvinyl alcohol copolymer. The modified polyvinyl alcohol copolymer has a good electrolyte resisting performance. The neutral and alkaline gel polymer electrolyte with ideal mechanical properties and capacitive properties is prepared by taking the modified polyvinyl alcohol copolymer as a matrix material, taking glutaraldehyde or borax as a cross-linking agent and adding a prop