The great amount of NH3-N produced in biological hydrolysis process of high concentration urea can inhibit the growth of microorganisms. In allusion to this problem, the Fenton reagent was used to treat high concentration urea wastewater. And the optimum conditions of this experiment were employed as follows: Fe (Ⅱ) -H2O2mole ratio was 1/3.53, H2O2 was 4 mL (corresponding to 35.30 mmol) , pH was 3.0 -3.5. Then the experiment shows that the urea concentration decreases from 500 mg/L to less than 2 mg/L, or is even not detected; under the same dose of H2O2 , repetitious addition does better than one-off addition; the reaction time within one minute or to be prolonged has little influence on removal effect. The results verify feasibility of this method.