NOVELTY - A lithium ion battery gel polymer electrolyte is prepared by reacting emulsifier, monomers of methyl methacrylate, acrylonitrile and vinyl acetate, and evocating agent; pouring white emulsion to a solution; adding aluminum sulfate; washing with deionized water and absolute ethyl alcohol; dissolving nanoparticles to N-N dimethyl formamide; adding and dissolving white polymer to obtain viscous solution; coating viscous solution on a glass board to obtain a film; immersing into deionized water; vacuum drying to obtain gel polymer film doped with nanoparticles; and immersing in electrolyte.    USE - Preparation of lithium ion battery gel polymer electrolyte (claimed).    ADVANTAGE - The gel polymer electrolyte has simple fabrication process, short preparation period, high production efficiency, higher decomposition voltage, greater ion electrical conductivity, and higher mechanical strength.    DETAILED DESCRIPTION - Preparation of lithium ion battery gel polymer electrolyte comprises:    (A) dissolving emulsifier (1-3 pts.wt.) to deionized water (60-70 pts.wt.) under nitrogen gas protection, adding and uniformly blending monomers of methyl methacrylate, acrylonitrile and vinyl acetate (27-36.8), and reacting evocating agent (0.1-0.4 pts.wt.) at 55-65 degrees C for 5-7 hours to obtain a white emulsion;    (B) pouring white emulsion to 1-1.5 times the volume of solution, adding aluminum sulfate (2-5 pts.wt.) to break the emulsion, washing with deionized water at 50-75 degrees C for 2-5 times, washing with absolute ethyl alcohol for 2-5 times to obtain a white polymer, and vacuum drying white polymer for 24-36 hours at 50-70 degrees C;    (C) dissolving nanoparticles to N-N dimethyl formamide (89-95 pts.wt.) at 60-80 degrees C, ultrasonically treating for 10-30 minutes, adding and dissolving white polymer (5-10 pts.wt.) to obtain viscous solution, coating viscous solution on a glass board to obtain a film with fixed thickness, and immersing the film into deionized water to obtain a white film; and    (D) washing the film with circulating water for 1-5 hours, immersing in deionized water for 1-3 hours, vacuum drying for 20-30 hours to obtain lithium ion battery gel polymer film doped with nanoparticles, and immersing gel polymer film in electrolyte for 20-40 minutes to obtain lithium ion battery gel polymer electrolyte doped with nanoparticles.    The nanoparticles are present at 1-20 wt.% of white polymer.