The degradation of C.I. Acid Red 73 (AR 73) was investigated by advanced Fenton process based on zero-valent iron and hydrogen peroxide. The effect of zero-valent iron dosage, hydrogen peroxide concentration, initial pH, initial dye concentration, mixing rate and temperature on the degradation of AR 73 was studied. The results showed that AR 73 removal efficiency increased with the increase of zero-valent iron addition, hydrogen peroxide concentration, mixing rate and temperature, but decreased with the increase of initial pH value. The residual concentration of AR 73 was only 6.4 mg/L after 30 min treatment at optimum conditions for 200.0 mg/L AR 73 initial concentration. And advanced Fenton process can partly remove COD values of AR 73. The activation energy of the degradation reaction is 31.98 kJ/mol. (C) 2009 Elsevier B.V. All rights reserved.