The invention discloses ink, comprising 20-35 parts of ink base, 5-10 parts of adsorbent, 0.01-0.05 part of polysorbate-80, 20-30 parts of reducer, 5-10 parts of titanate coupling agent, 5-10 parts of dispersant, and 1-5 parts of metal paste. The metal paste is silver or gold paste, the ink base is at least one of green ink, yellow ink, golden red ink or deep blue ink. Polysorbate-80 forms a protective layer on the surface of metal powder and adsorbent to be attracted with adsorbent with the polar group. A great deal of adsorbent contacts and is combined with the surface of the metal powder. The titanate coupling agent is of long-chain structure, epoxy resin is of three-dimensional mesh structure, and the polysorbate-80, the titanate coupling agent and the epoxy resin are made up of a special brightness enhancement film after ultrasonic treatment. Therefore, ink brightness after added with metal powder is increase by more than 20%. The more stable structure is formed under the combined action of the epoxy and the titanate coupling agent, so that ink can be kept in bright color for a long time.