The invention relates to the field of water proofing of 
metal roofs and particularly discloses a flash 
rust-proof acrylic roof waterproof 
coating which is prepared from, by weight, the following raw materials: 30-50 parts of an acrylic 
emulsion, 25-60 parts of antirust 
slurry, 1-5 parts of a 
plasticizer, 0.3-5 parts of a dispersing agent, 0.1-1 part of a defoaming agent, 0.1-1 part of a base material 
wetting agent, 0.1-2 parts of an anti-flash 
rust additive, 1-4 parts of a film forming assistant, 3-10 parts of water, 0.01-0.5 part of 
cellulose ether, 0.1-0.5 part of a bactericide, 0.01-0.5 part of a 
coupling agent and 0.01-0.5 part of a pH adjusting agent. The flash 
rust-proof waterproof effect of the roof waterproof 
coating with a flash rust-proof function is longer lasting than that of acommon 
metal roof waterproof 
coating, the anti-
ultraviolet effect is good, and the service life of a base material is prolonged. The waterproof coating has high elongation rate, good elasticity, strong base layer deformation resistance, the capability of shielding cracks, water proofing and breathability.