Objective To prepare a flame retardant agent for packaging paperboard with good flame retardant properties, and analyze its flame retardant properties. Methods Based on the safe and green properties as well as the application study of flame retardants in paper products, GP, MH and CMC were selected to prepare flame retardants. Tests and screening were conducted using GP as single composition and the blended formula for their flame-retardant performance, and the optimal formula as well as the preparation method for the safe and green flame retardant were analyzed and determined. Results The flame retardant paperboard packaging materials with the best performance were prepared when the concentration of the flame retardant Guanidine Phosphate (GP) was 10%, the dosages of magnesium hydroxide and CMC were 20 g/L and 10 g/L, the solvent was water, and the coating temperature was 60 ℃. Conclusion When B watts single corrugated cardboard was coated with flame retardant prepared using this formula, higher fire retardant grade was achieved.