Abstract: In this paper, transparent intumescent flame retardant coatings were prepared with melamine-formaldehyde resin（MF） as the film-forming resin, phosphoric acid-pentaerythritol（H₃PO₄-PER） as the intumescent flame retardant system, and graphene oxide（GO） as the flame retardant co-agent to improve the flame retardant and smoke suppression performance of wood-plastic composites（WPC）. Results showed that the coatings had highly transparency, good physical properties, excellent flame retardancy and smoke suppression properties. The addition of GO did not change the physical properties of the coatings, but significantly improved the thermal stability, flame retardancy and smoke suppression properties of the WPC composites. Thermogravimetric analysis（TG） tests showed that the charcoal residue of the coating increased by 11.0% when 0.2% GO was added. The simulated large plate burning method showed that the flame resistance time of the coating increased by 75.0% compared with the control group when 0.2% GO was added. Cone calorimeter（CONE） combustion test showed that the addition of GO effectively suppressed the heat release and smoke release of the coating. The total heat release and total smoke release of the coating decreased by 35.6% and 43.5%, respectively. The flake structure of graphene oxide became cross-linked points after the coating was expanded by heat, which improved the overall mechanical strength and stability of the carbon layer, and then achieved the effect of flame and smoke suppression.