Abstract: In this paper,Crucian was used as the raw material.A three factors three levels orthogonal test was used to confirm the optumum extracting conditions of acetyl cholinesterase(AChE)from the Cmcian liver so as to analyze the protein content and enzyme activity in the AChE coarse enzyme solution and compare the AChE activity and protein content in the liver and brain.As the enzyme restrain method was used to evaluate the restraining effects of dichlorvos,phoxim,triazophos,dimethoate in the coarse enzyme solution.The results of this study showed the pH,the type of the extraction solution and the quality volume ratio of the raw material to the extraction solution affect the activity of the enzyme significantly.Among the four organic phosphorus pesticides,dichlorvos shows the greatest restrain effect.

Key words: Crucian liver, acetylcholinesterase, organophosphorus pesticides, inhibition, extraction