Peracetic acid is an important industrial oxidizing agent, but it can be dangerous in the synthesis process. By reducing the reaction temperature, the safe factor in the preparation of high concentration peracetic acid can be improved; the synthesis technique of high concentration peracetic acid was studied, the effects of the dosage of concentrated sulphuric acid, the ratio of glacial acetic acid and hydrogen peroxide and other technological parameters concentration of peracetic acid were also studied. The results show that it is feasible to improve the safe factor by reducing the reaction temperature in the preparation process of peracetic acid; the origin reaction temperature can be controlled during 10 ~15 ℃ and reaction temperature controlled during 20 ~25 ℃; the best concentration of perhydrol is 50% and the dosage of sulphuric acid is 7%, meanwhile, the best volume ratio of glacial acetic acid and perhydrol is 1∶1.