Abstract:The susceptible populations and abamectin-resistance populations of Tetranychus cinnabarinus were selected to study the contents of free radicals (O2－ ·) and activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) treated with abamectin, high temperature and low temperature using the method of enzyme activity determination. The result showed that the free radical contents in the both populations were sharply raised, which was 3.42, 3.54 times higher than those of the control group, respectively, after 4h treated with abamectin. Meanwhile, the activities of SOD and CAT in treatment group were evidently higher than those in control group. In treatment group, the O2－ ·contents of the resistant populations were lower than those of susceptible populations, but the activities of SOD and CAT were opposite. The activities of O2－ ·, SOD, CAT and POD increased under unsuitable temperature. The maximum activities of SOD, CAT and POD in the susceptible populations were at 42℃ heat-shock, which were 4.25, 2.06, and 1.81 times higher than those in the control group, respectively, the difference was significant (P<0.05), and subsequently, there was a downward trend, but the enzyme activities in the resistant populations exhibited stably uprising tendency at experimental temperature. By analyzing the change ratio of enzyme activities, SOD had the strongest irritability to heat stress, POD took second place, the POD was the weakest and the change ratio of three enzyme activities in the resistant populations was higher than those in the susceptible populations.