Abstract: To study the mechanism of GABA receptor of organophosphates(OP)in vitro in order to give the evidencesof studying Op in vivo.Experiment use the model of rat's microsac to observe the change of ³HGABA bining to GABA receptor with diazino,soman,DFP,fenitrothion,azinphos ethyl,ethion acting in vitro.The ³HGABA binding of rat's microsac was significant decreased when 10mmol/L diisopropylfluorophosphate(DFP),fenitrothion,azinphos ethyl or 5mmol/L diazinon,soman were acted on the rat's microsac in virto(P<0.01).0.1mmol/L soman or 0.5mmol/L diaznon were acted on the rat's microsac in vitro,the ³HGABA binding were still significant decreased(P<0.05).The binding of GABA receptor was decreased when organophosphates were acted on the rat's microsac in vitro.