【目的】　探讨农药混配后农药之间发生的相互作用 ,为合理混配农药提供参考依据。【方法】　用等毒剂量法评价有机磷类与拟除虫菊酯类农药混剂对大鼠急性经口毒性的联合作用。【结果】　辛硫磷 +溴氰菊酯、辛硫磷 +高效氯氰菊酯、甲基对硫磷 +高效氯氰菊酯和水胺硫磷 +甲氰菊酯毒性增加非常明显呈现协同作用。辛硫磷 +氰戊菊酯虽属相加作用 ,但毒性是相加作用的 1 5倍 ,唯独敌敌畏 +溴氰菊酯虽属相加作用 ,但毒性略有降低。【结论】　有机磷与拟除虫菊酯混配常常能增加对哺乳类动物的毒性 ,并对所发生联合作用的性质 ,从毒代动力学、毒效动力学和所涉及的生化机制进行了讨论 【Objective】 To explore the interaction between pesticides after pesticide mixing, to provide a reference for rational mixing pesticides. 【Method】 The combined effect of organophosphate and pyrethroid pesticide mixture on acute oral toxicity in rats was evaluated by iso-dose method. 【Result】 The synergistic effects of phoxim + deltamethrin, phoxim + alpha-cypermethrin, methyl parathion + beta-cypermethrin and acetaminophen + fenpropathrin were observed. Phoxim + fenvalerate, although an additive effect, but the toxicity is additive effect of 15 times, except for dichlorvos + deltamethrin, although an additive effect, but a slight decrease in toxicity. [Conclusions] Organophosphorus and pyrethroid compounds often increase their toxicity to mammals and the nature of their combined effects is discussed in terms of toxicokinetics, kinetic kinetics and biochemical mechanisms involved