Abstract: Combined facultative-aerobic technology for dye-wastewater treatment was studied. Trial results showed that when COD of influent was 680～1 500 mg/L and the dye concentration was 102～517 mg/L,the average COD and color removal efficiency in the reaction system reached 96% and 94% respectively.Components and structures of the dye had been demonstrated to change during the process.The effect of facultative reactor was obvious.