The invention discloses a high-performance flame-retardant electrolyte. The high-performance flame-retardant electrolyte is prepared from the following raw materials in parts by weight: 80-90 parts of ethylene glycol, 5-10 parts of methylbenzene sulfonate, 5-10 parts of trifluoroacetate, 5-8 parts of polyethylene glycol, 1-2 parts of mannitol, 10-16 parts of silicon dioxide, 20-30 parts of boric acid, 5-15 parts of phosphoric acid, 25-35 parts of acid ammonium mixture, 1-2 parts of hydrogen eliminating agent and 1-3 parts of hydrolysis inhibitor. The high-performance flame-retardant electrolyte is resistant to high temperature and high voltage, and also capable of reducing hydrogen amount generated in the electrolyte working process and lowering electrolyte vapor pressure and hydrolysis reaction, and has flame retardancy; by virtue of the proper amount of added and deposited silicon dioxide, the fluidity of the electrolyte is improved, the adhesive property is lowered and difficulty in electrolyte pouring is effectively lowered; and meanwhile, the high-performance flame-retardant electrolyte is relatively low in cost of the preparation method, easily available in raw materials, simple and concise in process, and has high application prospect.