As cotton plant is treated with insecticides especially with pyrethroids, aphids and mites often increase. Understanding the effects of insecticide preparations on sugars and soluble proteins which are expected to be food niche and defensive compounds will help to predict the probable side-effects of them. The effects of five composite insecticide preparations on soluble proteins, total and reducing sugars, terpenoid aldehydes, and chitinase and peroxidase activities of the leaves of one Cotton cultivar were studied. Field experiments were carried in cotton fields of Tokshin district of Turpan region (Xinjiang Autonomous Region, China). The effects of insecticide preparations were reversely correlated with the activities of chitinase and peroxidase enzymes. The gained results showed that, after treatment with insecticide preparations, the quantity of soluble proteins increased whereas the activity of the PR proteins was lower than control leaves. Terpenoid aldehydes having anti-feedant properties also increased. All composite insecticides lowered the quantity of reducing sugars. However nonlinear changes were observed with the total sugars in cotton leaves after treatment.