The invention discloses a water-based anti-rust and heat insulation coating which is characterized in that the coating mainly consists of materials with following weight percentage: 10-30 percent of soft water, 0.1-0.3 percent of hydroxyethyl cellulose, 0.1-0.2 percent of preservative, 0.2-0.4 percent of anti-mildew agent, 0.2-0.5 percent of amine salt dispersant, 0.02-0.1 percent of low foam wetting agent, 0.1-0.3 percent of defoamer, 1-4 percent of glycol, 3-13 percent of coarse whiting, 3-20 percent of saponite, 18-25 percent of titanium pigment, 0.1-0.6 percent of organic amine, 3-6 percent of calcined kaolin, 28-43 percent of silicone-acrylate emulsion above Tg 35 DEG C, 1.3-2.8 percent of lauryl alcohol ester, 3-13 percent of hollow sodium silicate particle with the average grain size of about 10 to 30 Mum, 0.1-0.6 percent of thickener, 3-12 percent of wollastonite powder, and adjusting pH 10-pH 11. The invention is used for iron roofs and exterior walls etc., and has the advantages of good anti-rust and heat insulation effect, good durability, being easy for storage and coating, low cost and water environmental protection.