The invention provides a preparation method of oxidization-prevention flame-retarding coating. The preparation method comprises the following steps: uniformly mixing phenolic resin and nitrile butadiene rubber; continually adding dibenzoyl peroxide, pentaerythritol and salicylic acid and stirring; in a stirring process, raising the temperature to 100 to 120 DEG C at the temperature rising speed of3 to 6 DEG C/min; after keeping heat for 1 to 2h, cooling to room temperature to obtain modified phenolic resin; then carrying out ultrasonic treatment on the modified phenolic resin, ethyl cellulose, dibutyltin dilaurate and ethylene glycol butyl ether for 20 to 40min to obtain a mixed solution A; stirring and mixing waterborne polyurethane emulsion, pure acrylic emulsion, N-isopropylhydroxylamine and 2-naphthol-6-sulfonate; adding the mixed solution A and dropwise adding 0.2 to 0.5mol/L of sodium bicarbonate solution until the pH (Potential of Hydrogen) is 7 to 9; raising the temperature to130 to 150 DEG C at the speed of 4 to 8 DEG C/min; keeping the heat and reacting for 30 to 60min; then dispersing at a high speed for 20 to 40min; after cooling, obtaining the oxidization-preventionflame-retarding coating.