Objective To make a sensitive and specific method for quantitatively determination of hydrogen peroxide in water. Methods The strong oxide can oxidize potassium iodide to produce iodine in hydrochloric acid that reacts on amylum to produce iodine blue. In a range of concentration the colour of iodine blue accords with Bill's law. Firstly the gross of hydrogen peroxide and the other strong oxides in the sample were determined. Secondly, on the action of catalase the hydrogen peroxide was decompounded into oxygen and water, then, hydrogen peroxide lost its characteristic of oxidation, the other oxides without hydrogen peroxide in the sample were determined. The difference of the two determined results is the content of hydrogen peroxide. Results The calibration curve was linear between 0 to 2 ?g/ml (10 ?g/5 ml). The relative standard deviation was less than 1.2%. The rates of recovery were 98.7%-101.3%. The detection concentration was 0.08 mg/L(0.08 ?g/ml). Conclusion This method is simple, rapid, sensitive and hardly to be disturbed by any other strong oxidizers. This method is suitable for trace hydrogen peroxide analysis of source water and drinking water.