The commercial acetylcholinesterase (AChE) from Musca domestica, and the acetylcholinesterase made by the researchers themselves from fowl liver and cyprinoids brain, were used for pesticides detection. The inhibition of AChE activity under different concentrations of omethoate, trichlorfon and dichlorvos were compared. The results show that the inhibition of AChE activity of Musca domestica is the highest of the three above. Three kinds of Acetylcholinesterase are not sensitive to omethoate. AChE from cyprinoids brain can be used for rapid detection of dichlorvos in the case of high detection precision is not needed. AChE from fowl liver can be used for rapid detection of trichlorfon.  