The invention discloses an ABS modified material with high heat resistance, high gloss and flame retardance and a preparation method thereof. The material comprises ABS, SAN (Styrene Acrylonitrile), a flame retardant, a heat resistant agent, a compatibilizer, an antioxidant and a lubricating agent. The preparation method comprises the steps of: weighing raw materials; sequentially adding the raw materials into a high mixing machine in a material mixing sequence; stirring and mixing for at least 2 minutes; putting the mixed raw materials into a double-screw extruder for extruding and granulating, wherein the screw rotating speed is 200 to 450 revolutions/minute, the screw temperature is 180 DEG C to 220 DEG C, the residence time is 1 to 2 minutes and the melt pressure is 10 to 20Mpa; extruding to obtain particles; and drying the particles at 60 DEG C to 90 DEG C for 2 to 4 hours. The invention provides the ABS modified material which achieves high heat resistance, flame retardance and high gloss.