The invention belongs to the technical field of biology, more particularly relates to an application of laccase in protein gel decoloration, and specifically relates to an application of laccase in decoloration of protein gel electrophoresis after conventional dyeing. The application aims at decoloring dyed protein gels by using laccase; and the application is environment-friendly, rapid, simple and convenient, does not need organic solvents, and can be used for saving energy and reducing the pollution caused by dye wastewater. According to the application of decoloring the protein gels by using laccase, disclosed by the invention, rapid decoloration can be achieved (a low-background clear protein band can be obtained within 2 hours), simplicity and convenience in operations can be achieved (boiling or decoloring liquid replacement is not needed), and environmental protection can be achieved (organic solvents such as methanol and acetic acid required by conventional decoloring liquid are not used, dye degradation can be achieved while decoloring, and no waste liquid treatment problems and cost can be produced). According to the application, by optimizing factors such as laccase concentration, medium types and concentration and decoloring time, good decoloring effects can be achieved in a relatively short time, and simplicity and convenience in operations and environmental protection can be achieved.