Waterproof pressure steam sterilization indicator and preparation method thereof

The invention relates to the technical field of indicating ink, in particular to a waterproof pressure steam sterilization indicator and a preparation method thereof. The waterproof pressure steam sterilization indicator comprises a color-changing ink layer and a waterproof ink layer compounded on the color-changing ink layer, the preparation raw materials of the color-changing ink layer comprise a metal compound, a sulfur-containing compound, a pigment, polymer resin, a first solvent and an antioxidant according to a certain ratio; the metal compound comprises at least one of a copper-containing compound, an iron-containing compound and a bismuth-containing compound; the preparation raw materials of the waterproof ink layer comprise a film-forming agent, a thickening agent, a plasticizer and a second solvent according to a certain ratio. According to the invention, the color-changing ink layer can change color after steam sterilization, the color can be changed from yellow to black, green to black or blue to