A　uniform　and　stable　ferroferric　oxide　supported　graphitized　carbon　black　magnetic　nanomaterial　(GCB/Fe3O4)　was　prepared　by　crystal　formation　method.　The　crystal　structure,　surface　morphology　and　magnetic　properties　of　GCB/Fe3O4　were　investigated　by　scanning　electron　microscopy　,　Fourier　transform　infrared　spectroscopy,　X-ray　diffraction　and　vibrating　magnetometer.　The　adsorption　properties　of　GCB/Fe3O4　pigment　,　polyphenol　and　other　interfering　substances　were　studied　by　taking　catechin　,　curcumin　,　quercetin　,　chlorophyllin　and　beta-carotene　as　objects.　The　results　showed　that　the　magnetic　nanomaterials　GCB/Fe3O4　retained　the　original　adsorption　characteristics　of　GCB　successfully　and　possessed　magnetism.　The　saturated　adsorption　capacity　of　catechin　,　curcumin　,　quercetin　,　chlorophyllin　and　beta-carotene　were　7.　87　,　9.　19　,　5.　65　,　3.　35　and　6.　13　mg/g　,　respectively,　which　were　increased　by　187.　2%　,　28.　9%　,　55.　2%　,　52.　3%　and　4.　6%　,　respectively,　in　comparison　with　GCB.　GCB/Fe3O4　was　used　as　magnetic　adsorbent　to　purify　405　kinds　of　pesticide　residues　in　tea.　Compared　with　the　current　solid　phase　extraction　or　QuEChERs　,　the　operation　was　simpler　and　faster,　and　the　purification　time　could　be　saved　by　more　than　15%　.　The　recoveries　of　393　kinds　of　pesticide　residues　in　tea　were　60%　-　120%　,　and　the　relative　standard　deviations　were　2.　6%　-　14.　6%.　The　experimental　results　showed　that　the　prepared　GCB/Fe(3)O(4　)had　good　adsorption　properties　and　good　stability,　and　could　be　used　for　sample　pretreatment　of　pesticide　residues　in　tea.