目的 对河北省不同地区德国小蠊野外种群和室内敏感种群的乙酰胆碱酯酶（AChE）、多功能氧化酶（MFO）、羧酸酯酶（CarE）和谷胱甘肽-S-转移酶（GSTs）的活性进行测定，并用相关系数和通径系数分析酶活性与抗性水平的关系，探讨德国小蠊抗药性发生的生化机制。方法 利用生理生化检测法对德国小蠊（2014－2015年在河北省8个市，采集德国小蠊成虫和若虫，饲养室内繁殖后的2～3周龄成虫）体内各种酶活性进行检测，采用相关性及通径分析法对酶活性与抗性水平的关系进行分析。结果 承德市德国小蠊种群对毒死蜱的抗性水平最高，抗性倍数为25.32倍；唐山种群对氯氰菊酯及高效氟氯氰菊酯的抗性水平最高，抗性倍数分别为37.45和23.92倍；各地德国小蠊野外种群中CarE、MFO-氧-脱甲基活性均明显高于敏感种群，AChE及GSTs活性差异较大。抗药性水平与酶活性关系的通径分析结果表明，CarE活性对毒死蜱抗性水平起主要增进作用，决策系数为0.122 8；MFO活性对高效氟氯氰菊酯和氯氰菊酯的抗药性水平起主要增进作用，决策系数分别为0.283 8和0.512 1。结论 CarE与德国小蠊野外种群对毒死蜱的抗性有关，AChE与德国小蠊对毒死蜱和氯氰菊酯的抗性有关，MFO与德国小蠊对氯氰菊酯和高效氟氯氰菊酯的抗性有关，GSTs在河北省德国小蠊野外种群对3种杀虫剂抗性水平中的作用不大。

Objective The activities of acetylcholinesterase, multifunctional oxidase, carboxylesterase and glutathione-S-transferase in the field populations and susceptible populations of Blattella germanica were determined. Correlation coefficient and path coefficient were used to explain the relationship between enzyme activity and resistance levels of different insecticides. To explore the resistance mechanism of field populations of B. germanica in Hebei province. Methods During 2014-2015, adults and nymphs of B. germanica. were collected in 8 cities of Hebei province, 2-3 weeks old adults were reared indoors. The activities of enzyme activities were measured by physiological and biochemical methods, and the relationship between enzyme activity and resistance level was analyzed by correlation and path analysis. Results The resistance level of Chengde B. germanica populations to chlorpyrifos was the highest, the resistance index was 25.32 times. The resistance of level to cypermethrin and the beta-cyfluthrin in the B. germanica populations of Thangshan was the highest, with the resistance index of 37.45 and 23.92 times respectively. The activity of CarE and MFO-oxygen-demethylation in the wild populations were significantly higher than that in susceptible populations, and activity of AChE and GSTs were different. The relationship between resistance level and enzyme activity of path analysis showed that CarE activity had a major enhancement effect on the resistance level of chlorpyrifos, and the decision coefficient was 0.122 8. The MFO activity has a major contribution in the resistance level to beta-cyfluthrin and cypermethrin. The decision coefficient was 0.283 8 and 0.512 1 respectively. Conclusion Carboxylesterase was related to chlorpyrifos resistance in field populations of B. germanica. Acetylcholinesterase was associated with resistance to chlorpyrifos and cypermethrin. Multifunctional oxidase was associated with resistance to cypermethrin and beta-cyfluthrin. Glutathione-S-transferase had little effect on the resistance level of the three insecticides in field populations of B. germanica in our province.