Abstract: Al3+-doped ZnO submicron rods were synthesized by one-step precipitation reaction in solution and characterized by X-ray diffraction (XRD) for crystal structure and scanning electron microscopy (SEM) for morphology. The effects of key operating parameters, such as initial pH value, concentrations of H2O2, Co2+ and dyestuff, Zn(Al)O dosage, temperature and ultrasonic time on degradation of methylene blue (MB) were studied. Four different decoloring method were compared on the degradation ratio of MB. The optimal condition for degradation of MB was that under Co2+-Fenton process with ultrasound-assisted for 1 h, the most efficient removal ratio for 80 mg/L MB solution was 72% with the conditions of pH 5-9, H2O2=100 mmol/L, Co2+=0.1-0.3 mmol/L, Zn(Al)O=1.0 g/L, and reactive temperature 30-50C. The degradation mechanism for the system of Fenton/Co2++Zn(Al)O+US was discussed. In addition, the recycling experiments of Zn(Al)O were performed three times and the degradation ratios were 72%, 68% and 46% for the 1st, 2nd and 3rd time, respectively. Under natural sunlight with ultrasound-assisted, the degradation ratio of MB in the presence of Zn(Al)O was 1.8 times as great as P25 (degradation ratio is 40%). Results indicated that this degradation method has a good application prospect.