用酶标仪动力学测定法对3个抗性水平不同的棉蚜品系（R1、R2和R3）和1个敏感品系（S）的羧酸酯酶进行了研究，S、R1、R2和R3品系对α-乙酸萘酯（α-NA）的平均比活力分别为57．10、1171．69、1236．14和3293．00μmol·mgpro－1·min-1（分光光度计终点测定法）和38．24、85．27、198．14和762．25mOD·min－1·aphid-1（酶标仪动力学法）。终点测定法结果显示出不同品系间最大相差达60倍；酶标仪动力学测定法研究表明，4个棉蚜品系羧酸酶活性与其抗药性程度显著相关。通过对这两种方法的比较，酶动力学方法的测定结果更可靠。 Carboxylesterase activities of three susceptible cotton aphid lines (R1, R2 and R3) and one sensitive line (S) were studied by microplate kinetic assay. S, R1, R2 and R3 The average specific activity of α-NA for the strain was 57.10, 1171.69, 1236.14 and 3293.00 μmol · mgpro-1 · min-1 (spectrophotometer endpoint assay) and 38.24, 85.27, 198.14 and 762.25 mOD · min-1 · aphid-1 (microplate kinetic method). The result of endpoint assay showed that the maximum difference between different strains was 60 times. The kinetic assay of microplate reader showed that the carboxylesterase activity of four cotton aphids significantly correlated with the degree of drug resistance. By comparing these two methods, the results of enzymatic kinetic methods are more reliable.