NOVELTY - A self-supporting gel polymer electrolyte is prepared by dissolving emulsifying agent into deionized water, adding monomers of n-butyl methacrylate and styrene, heating, reacting evocating agent, pouring emulsion into solution, agitating with aluminum sulfate, washing with water, vacuum drying white polymer, dispersing nanoparticles, dissolving into tetrahydrofuran, adding white polymer, dissolving, dipping obtained viscous solution into deionized water, washing achromatous transparent film with water, dipping in deionized water, airing, vacuum drying, and dipping in electrolyte.    USE - Preparation of self-supporting gel polymer electrolyte (claimed) for industrial production of polymer lithium ion battery.    ADVANTAGE - The gel polymer electrolyte has good thermal stability, high decomposition temperature, easy and simple preparation process, and low cost.    DETAILED DESCRIPTION - Preparation of self-supporting gel polymer electrolyte comprises:    (A) dissolving emulsifying agent (1-3 pts.wt.) into deionized water (60-67 pts.wt.) under protection of inert gases, agitating, sequentially adding monomers of n-butyl methacrylate and styrene (30-37 pts.wt.), heating to 55-65 degrees C, and reacting for 0.5-2 hours;    (B) adding evocating agent (0.1-0.4 pts.wt.), agitating and reacting for 6-10 hours to obtain a white emulsion, pouring emulsion into 1-1.5 times the volume of solution, agitating with aluminum sulfate (2-5 pts.wt.) to break emulsion, washing with water to obtain a white polymer, and vacuum drying white polymer for 24-36 hours at 50-60 degrees C;    (C) ultrasonically dispersing nanoparticles at 30-35 degrees C for 10-30 minutes using an ultrasonic disperser, dissolving into tetrahydrofuran (89-95 pts.wt.), adding white polymer (5-10 pts.wt.), dissolving, collecting obtained viscous solution onto glass plate, and dipping into deionized water to obtain an achromatous transparent film; and    (D) washing the film in circulating water for 2-8 hours, dipping in deionized water for 2-5 hours, airing at normal temperature to obtain self-supporting gel polymer film, vacuum drying gel polymer film at room temperature for 5-8 hours, and dipping in electrolyte for 20-40 minutes to obtain the gel polymer electrolyte.    The nanoparticles are present at 0-20 wt.% of white polymer.