The invention relates to the technical field of corrosion inhibitors, particularly a scale and corrosion inhibitor which is composed of the following components in percentage by weight: 30-40% of 2-hydroxyphosphoacetic acid, 15-20% of hydroxyethidene diphosphoric acid, 20-30% of bis 1,6-hexylidenetriaminopentamethylene phosphonic acid, 1-3% of polyacrylic acid, 5-15% of zinc sulfate and the balance of water. The scale and corrosion inhibitor has obvious action on circulating water with high temperature and various pH values, wherein the corrosion rate for carbon steel is lowered to 0.00871mm/a, and the corrosion rate for stainless steel is lowered to 0.0000906mm/a.