The invention discloses a flame-retardant shell material for battery car chargers. Raw materials of the flame-retardant shell material comprise, by weight, 125-130 parts of a base material, 2-10 partsof modified Sa-son seed gum, 0.3-1 part of disproportionated rosin, 1-2 parts of zinc stearate, 0.4-1 part of 2-ethylhexyl 9,10-epoxyoctadecanoate, 1.5-2.5 parts of a cross-linking agent, 20-30 partsof magnesium hydroxide, 4-12 parts of melamine formaldehyde resin, 8-12 parts of white carbon black, 10-16 parts of coal gangue, 2-8 parts of calcined kaolin, 10-16 parts of sepiolite powder and 0.1-0.6 part of a titanate coupling agent. The modified Sa-son seed gum is prepared by the following steps: stirring Sa-son seed gum, lactalbumin and water, adding the polyurethane fibers and glycerol triglycidyl ether, performing stirring, introducing nitrogen until saturation, adding potassium persulfate, heating and stirring the obtained mixture, filtering the mixture to obtain a precipitate, washing the precipitate, and drying the washed precipitate to obtain the modified Sa-son seed gum.