Ionic liquid modified graphene(IL-GR) was firstly dispersed in polyvinyl alcohol(PVA) to form IL-GR-PVA dispersion,then IL-GR-PVA and acetylcholinesterase(AChE) was mixed evenly and was coated on the glass carbon electrode via PVA film-forming.A novel biosensor was developed for the detection of organophosphorus pesticide(OP).Different techniques were employed to study the construction process and the electrochemical properties of the biosensor.The IL-GR-PVA nanocomposites with excellent conductivity and biocompatibility offered an extremely hydrophilic surface for AChE adhesion.Linear relationship between the inhibition percentage(I%) and logarithm of phorate concentration was found in the ranges of 1.0×10-14-1.0×10-9 mol/L and 1.0×10-9-1.0×10-6 mol/L,with a detection limit(S/N=3) of 8.0×10-15 mol/L.The easily prepared electrochemical sensor has a favorable stability and sensitivity,thus providing a new OPs detection method