Acetylcholinestemse (ACHE) is normally associated with the breakdown of acetylcholine in the synapse and the neuro-muscular junction. The monoclonal antibodies(McAb) against acetylcholinesterase can be not only used to study the structure and function but also used in immunohistochemistry as specific sophisticated molecular probes,in order to know the cross immunoreactivity between the McAb and AChE from various sources the antigen-antibody reaction was assayed by enzyme linked immunosorbent assay. Rat and mouse brain AChE, erythocyte ACHE, and sera butyrylcholinesterase were coated onto microplate followed by incubation with McAb.The results showed that McAb 2E6 against Torpedo AchE reacted well with Acetylcholinestemse (ACHE) is normally associated with the breakdown of acetylcholine in the synapse and the neuro-muscular junction. The monoclonal antibodies (McAb) against acetylcholinesterase can be not only used to study the structure and function but also used in immunohistochemistry as specificphased molecular probes, in order to know the cross immunoreactivity between the McAb and AChE from various sources the antigen-antibody reaction was assayed by enzyme linked immunosorbent assay. Rat and mouse brain AChE, erythocyte ACHE, and sera butyrylcholinesterase were coated onto microplate followed by incubation with incubation McAb. The results showed that McAb 2E6 against Torpedo AchE reacted well with