Abstract: This paper used the starch as the raw material to prepare three different kinds of flocculants which are acrylamide-grafted starch, starch phosphate and cationic starch ether. Treating the wastewater using the flocculants, the influences of dosage, pH value and temperature on flocculating performance were studied taking the suspended solids concentration, COD removal efficiency and removal rate of Cu²⁺ as indexes. Result showed that when the dosage of the acrylamide-grafted starch was 6 mg/L, the pH value was 7～9 and the temperature was 25 ℃, the best result was gotten. When the dosage of starch phosphate was 12 mg/L, the pH value was 7 and the temperature was 25～35 ℃, the best result was gotten.When the dosage of cationic starch ether was 14 mg/L, the pH value was 7 and the temperature was 25～35 ℃, the best result was gotten. The acrylamide-grafted starch could get the best treatment effect, while the cationic starch ether followed and the starch phosphate gained the last name.