The invention discloses a preparation method of polyurethane paint with flame retardance, light resistance and low VOCs (volatile organic compounds). According to the method, 0.22g of triethylene tetramine, 70g of polytetrahydrofuran ether glycol and 15g of hexamethylene diisocyanate are added into a 250ml flask with three necks, wherein the flask with three necks is provided with a stirrer, a condensation tube and a thermometer; the reaction is performed for 2h at 80 DEG C to obtain a polyurethane prepolymer A; 0.62g of acetamide and 8.2g of ethyl methyl ketone are added into the prepolymer A; the reaction is performed for 3.5h under the condition of 75 DEG C; 2g of modified manganese hypophosphite prepared in the first step, 4g of 4-carboxyphenylboronic acid and 2.5g of diethylenetriaminepenta acid are added; the reaction temperature is 80 DEG C; the reaction time is 2h; 7.1g of triethylamine is added for neutralization reaction for 60min; 0.9g of vitamin C and 70g of water are added for stirring and emulsification; the polyurethane paint with flame retardance, light resistance and low VOCs is obtained. The prepared polyurethane paint with flame retardance, light resistance and low VOCs achieves an environment-friendly effect, has low cost, is widely applied to surfaces of walls, furniture and hardware, and is used as a bonding agent of plastics, glass, papermaking and spinning.