Dye wastewater has complex structures and is difficult to be biodegraded. Three-dimensional electrolysis is advantageous in mass transfer and oxidation degradation ability. In this paper, a continuous flow three-dimensional electrolytic reactor with coconut shell activated carbon as the filling material is established to treat methyl blue dye wastewater. The influence on the dye wastewater treatment by the pH value of the system, the impressed voltage, the concentration of electrolyte, the aeration rate, the electrolysis time and the interactions of the five factors on COD degradation are investigated in the experimental part, and the optimal degradation condition is finally determined. Results show that it not only improved the degradation efficiency of dye wastewater, but also help to energy conservation, emission reduction and sustainable development.