[ Objective ] The paper was to systemically study the characteristics of acetyl cholinesterase （ACHE） in Pardosa astrigera, and confirm the occurrence and development of its pesticide resistance and the resistance level, thereby establishing a quick and accurate detection method for enzyme activity. [ Method] The optimal conditions for assaying the activity of AChE in different parts of P. astrigera were determined by orthogonal experiment. The distribution conditions of acetyl cholinesterase （AChE） in different tissues of P. astrigera were further studied, and the sensitivities of the enzyme tO four common pesticides were also determined. [ Result] The optimal condition for assaying the activity of AChE in cephalothorax, abdomen and appendage of P. astrigera was as follows, enzyme concentrations： 12, 18 and 29 g/L; substrate concentrations： 0.6, 1.0 and 1.0 mmol/L; pH value, 7.0; reaction temperatures： 30, 35, 35℃ ; reaction time, 5 rain. AChE was mainly distributed in the cephalothorax of P. astrigera. The specific activity of AChE in the extract solution with Triton X-100 was higher than that in the solution without Triton X-100. The median inhibitory concentrations （IC50） of methomyl, phoxim, betacypermethrin, chlorpyrifos against AChE in the cephalothorax of P. astrigera were 7.76 × 10^-5, 1.76×10^-4, 4.12 ×10^-4 and 4.94 ×10^-4 mol/L, respectively. [ Conclusion] AChEs in P. astrigera were membrane-bounded. The inhibition of four pesticides against AChE in the cephalothorax of P. astrigera had good dese-effect, this indicated that AChE in the cephalothorax of P. astrig- era could be used as the biochemical marker to monitor the contamination of organic phosphorus, carbamate and pyrethroid pesticides in the environment.
