In this paper, the environmentally-expandable flame retardant coating which can be used for the wire mesh was prepared by APP, MEL and PER as intumescent flame retardants, expandable graphite as flame retardant synergist, silicone-acrylic emulsion as film-forming substance, titanium dioxide as film-forming substance, titanium dioxide as pigment filler and water as solvent. The optimum ratio of intumescent flame retardant was determined by orthogonal experiment. The types of film-forming materials and flame retardant synergists were screened and the optimal addition amount was optimized by single variable factors.The result showed that when the amount of silicone-acrylic emulsion is 30%, m(ammonium polyphosphate)∶m(melamine)∶m(pentaerythritol)∶m(expandable graphite) =20∶15∶13∶2, the intumescent flame retardant coating had good flame retardant properties.