Abstract: To explore the degradation mechanism of dyes, the ligninolytic enzyme system was investigated in detail by analyzing the enzyme activity of laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP). At the same time, the decolorization effects on three kinds of chemical dye to fermentation liquid in different treatments were studied. The results showed that under liquid culture condition, the dyes could both be adsorbed by mycelium and transformed by the ligninolytic enzyme system which was secreted by Flammulina velutipes fermentation. However, the key substances to chemical dyes’ transformation was not laccase but mycelium adsorption, and the adsorption to different chemical dyes had certain selectivity. The adsorption effect of the dyes by the inactivated mycelia and the non killed mycelia was also different, which suggested that the temperature could change the surface structure of the cell and make it easier to adsorb the dyes in the solution. This study had essential application value for the current treatment of dyes.