In　this　study,　Fe3O4@ZrO2　magnetic　core-shell　nanoparticles　(NPs)　were　synthesized　and　were　characterized　by　transmission　electron　microscopy　(TEM),　X-ray　diffraction　(XRD)　and　X-ray　photoelectron　spectroscopy　(XPS).　Fe3O4@ZrO2　NPs　were　modified　onto　the　surface　of　a　magnetic　glassy　carbon　electrode　(MGCE)　to　prepare　an　electrochemical　sensor　(Fe3O4@ZrO2/MGCE).　The　voltammetric　behaviours　of　methyl　parathion　(MP)　at　the　Fe3O4@ZrO2/MGCE　were　studied　by　cyclic　voltammetry.　A　sensitive　and　simple　method　for　determination　of　MP　was　developed　based　on　the　strong　affinity　of　ZrO2　of　the　sensor　to　phosphoric　moieties　of　organophosphate　compounds　(OPs).　The　electrochemical　sensor　was　successfully　applied　to　determine　MP　by　square-wave　voltammetry　(SWV).　Under　optimal　conditions,　the　cathodic　peak　current　of　MP　showed　a　highly　linear　increase　with　MP　concentrations　over　the　range　of　7.60　x　10(-8)　M　to　9.12　x　10(-5)　M,　with　a　detection　limit　of　1.52　x　10(-8)　M.