Abstract: The cholinesterases (ChE) show high sensitivity and specificity to inhibition by organophosphate compoundes,but cholinesterases from different biological materials have large difference in the sensitivity.The cholinesterases from Pseudosciaena polyactis,P.crocea,Argyrosomus argentatus,Miichthys miiuy and Nibea albiflora of the Sciaemidae of Perciformes are very sensitive to Sarin (Isopropyl- methyl- phosphonfluoridate) and VXO-ethyl- s-( 2- diisopropylaminoethyl) methylphosphonothiolate,the PI50 values to Sarin and VX are over 7.0.They will become a effective biological reagent for analysis of organophosphate compoundes and insecticides after further experiments,which may have some guiding significance in screening substances with biological activity.