The simulated dye wastewater containing alizarin red S (ARS) was electrochemically oxidized using an activated carbon fiber (ACF) felt as an anode. The removal efficiency of color and chemical oxygen demand (COD) was evaluated by comparing ACF adsorbents with ACF anodes. The experimental results show that the electrochemical oxidation method using ACF as anode can effectively remove dyestuff pollutant from wastewater. About 98% of the color removal ratio and 76.5% of the maximum COD removal ratio are achieved after 60 min of electrolysis. It is suggested that ARS was adsorbed and concentrated on the ACF anode due to its high surface area; the simultaneously electrochemical oxidation of the ARS may regenerate the ACF anode, which enhance the electrolysis efficiency of the ARS.