The new purifying agent named granulated fly ash was used to absorb the organic dyes-ethylene blue, direct red 12B and reactive brilliant orange X-GN in solution in this paper. The effects of dosage, temperature and pH on adsorption and discolor were separately studied. In addition, the adsorption model was also analyzed. Experiment results showed that adsorption isotherm models of ethylene blue and direct red 12B on the new agent conformed to Freundlich equation, and reactive brilliant orange X-GN conformed to Langmuir equation; The adsorption kinetics models of ethylene blue, direct red 12B and reactive brilliant orange X-GN on the new agent conformed to pseudo-secondary kinetic equation, liquid film diffusion was the main control step for adsorption of the three dyes.