PolyrhAChis vicina roger as social insects belong to Insectea, Hymenoptera, Formicidae, PolyrhAChis. There are well-defined grades and division of labour in P.vicina, which possess a complex neverous system. The P. vicina brain mushroom bodies are development very well, which may become a good material to investigate the animal behaviors.Acetylcholine esterase （AChE） is a kind of critical enzyme, which degradates acetylcholines in the cholinergic synapse to end the stimulation on postsynaptic membrane and ensure the nerveal signal transmition.. AChE is also the target of orgnaophosphorus and carbamate pesticides which inhibit the activity of AChE to intercept the nerve impulse and lead to the insect death. On these grounds, various kinds of pesticides are devised. Some investigation report that senile dementia is improved by inhibit the activity of AChE.AChE were discovered not only in the nerve cells, but also in other cells, the apoptosis cells are also show positive reactivity. Lots of experiments indicate that AChE have many functions. There are two kinds of cholinesterase in the mammal bodies, but there is only one kind of cholinesterase discoved in the insect bodies, and which holinesterase is simple. The location of AChE in the P. vicina brains and bodies in different stages has been inverstigated. The conclutions are offered as follow.1 The whole brain regions of P. vicina have AChE positive reaction, the comparition of AChE in the brain during the adult stage shows that there are the stronger positive reaction in the tritocerebrum, suboesophageal ganglion and deutocerebrum, secondly in the central complexes, optic lobes and calyxes, lastly in the pedunculus and lobes. The comparition of AChE in the sub-brain between three grades show that there are weaker positive reaction in the spado optic lobes than gyne and aner’s. There are not significant discrepancy among calyxes. The pedunculus and lobes of aner have the weakest positive reaction among three grades . The positive reaction of gyne central complex is stronger than the other grades. There are the weakest positive reaction in the spado deutocerebrum. The positive reactions of tritocerebrum have not significant discrepancy within three grades. The location of AChE in the spado’s mushroom bodies are that, there are the strongest positive reaction in the lip, collar and basal region, there are stronger in the lobes, and the positive reaction in the pedunculus are the weakest. The location of AChE in the spado’s brain during the pupal stage show that there are strongest positive reaction in the deutocerebrum, secondly in the tritocerebrum and suboesophageal ganglion, then in the central complexes, optic lobes, lastly in the pedunculus and lobes.2 We observe the location of AChE during different stages which include larval stage, pupal stage, adult stage. The result shows that there are all have positive reaction in the nerve fibres, glia cells, synapses and lympholeukocytes, which indicates that AChE may play important functions in those area.3 The central nerve development of P. vicina: （1） The brain development of P. vicina. P. vicina brains have not fomation in the larval stage, only a rod-shape structure is found conjointing ganglion subpharyngeale. The brain of pupal stage, has not well development very well, though the optic lobes, mushroom bodies, medial complex, deutocerebrums, tritocerebrums and suboesophageal ganglion can be found, the subregions of mushroom body can not be distinguished. The neuropiles of brain are rarefaction, especially the mushroom body’s. The structure of brain is formation in the adult stage, the neuropiles of brain are intensive. The mushroom body is development very well, the subregions of which are distinguished easily. （2） The P. vicina ventral nerve chain changes from the larval stage to adult stage obviously. The suboesophageal ganglions are two rod-shape structure, eACh of which is followed by one piece of nerve chain, throuh the thoracic part and split into two part extending into abdominalis in the larval stage. The ventral nerve chain is in ladder shape, the two ventral nerve chain draw closely and the dorsi-ventrally zygomorphic ganglions concrescented to compare with the larval stage’s, the ganglions are legume shape firstly, then concrescented wholly and present on orbicular-ovate, hemicycle or metuliform. The ventral nerve chain within thoracic part like a ladder, the nerve chain between the first ganglion and the second ganglion are longer than the nerve chain between the second ganglion and the third one, and the chains between the second ganglion and the third one are concrescented to eACh other. The adult ventral nerve chains concrescence tighter than the pupal stage’s, the chain between the second ganglion and the third one is narrower, but have stronger positive reaction.