The toxicity of eight conventional insecticides to the third-instar Apolygus lucorum was measured at 15°C, 20°C, 25°C, 30°C, and 35°C, and the temperature was strictly maintained from pretreatment to posttreatment. The results showed that temperature prompted a slightly positive influence in toxicity of phoxim and carbosulfan, whereas methomyl was negatively influenced by temperature. β-cypermethrin and λ-cyhalothrin demonstrated a distinctively stable negative temperature coefficient, especially β-cypermethrin with a 70.27 time variance between given temperatures. In contrast, the toxicity of imidacloprid and acetamiprid increased as the temperature rose, showing a significant positive temperature coefficient to Apolygus lucorum. The effect of temperature on the toxicity of fipronil was irregular. Therefore, temperature should be taken into account in the process of choosing insecticides.