Potato starch wastewater belong to high concentration organic wastewater. Study on potato starch wastewater treatment by Fenton reagent, the results showed: the optimal value of H2O2/Fe2+ is 5:2, the COD removal amount achieving a maximum of 48.5gCOD/molH2O2.The COD removal amount reach to the highest when pH value was about 7.02, so that the actual potato starch wastewater treatment by Fenton needn’t pH regulation. Fenton oxidation rate is high, with little affected by temperature, so the treatment is applicable to potato starch wastewater with low temperature in northern region of China.