Abstract: The partial purification of glutathione S-transferases (GST) in  larvae of the cotton bollworm, Helicoverpa armigera (Hübner) was studied using ammonium sulfate fractionation after polyethylene imine (PEI) fractionation, polyethyleneglycol (PEG) fractionation and GSH-Sepharose 4B. The results showed that efficacy of purification by PEG10000 and PEG20000 was better than that of ammonium sulfate fractionation after PEI fractionation. After wiping off nucleic acid using PEI fractionation, the peaks of GST activities were in 70%－75% and 60%－65% of ammonium sulfate fractionation for midgut and fat body, respectively; the specific activities were 1 081.49 and 596.41 nmol/(min·mg), and purification factors were 2.53-fold and 2.2-fold, respectively. The efficacy of purification by PEG10000 and PEG20000 was the best in six kinds of PEG tested. The activity peaks of GST were in 40%－45% and 30%－40% of PEG10000 fractionation for midgut and fat body, respectively; the specific activities were 795.11 and 1 080.18 nmol/(min·mg), and purification factors were 2.4-fold and 3.97-fold, respectively; the activities of GST were the highest in 25%－40% and 25%－45% of PEG20000 fractionation for midgut and fat body, respectively. The specific activities of GST were 767.57 and 945.96 nmol/(min·mg) respectively, and the purification factors were 2.81-fold and 3.05-fold. The specific activity of GST from midgut reached 5 888.44 nmol/(min·mg)  by GSH-Sepharose 4B column chromatography and the purification factor increased to 107.38-fold.