Rhythmofbrainactivitiesrepresentsoscillationsofpostsynapticpotentialsinneocortex,thereforeitcanserveasanindicatorofthebrainactivitystate.Inordertochecktheconnectivityofbrainrhythm,thispaperdevelopsanewmethodofconstructingfunctionalnetworkbasedonphasesynchronization.Electroencephalogram(EEG)datawerecollectedwhilesubjectslookingatagreencrossintwostates,performinganattentiontaskandrelaxingwitheyes-open.TheEEGfromthesetwostateswasfilteredbythreeband-passfilterstoobtainsignalsoftheta(4-7Hz),alpha(8-13Hz)andbeta(14-30Hz)bands.Meanresultantlengthwasusedtoestimatestrengthofphasesynchronizationinthreebandstoconstructnetworksofbothstates,andmeandegreeKandclustercoefficientCofnetworkswerecalculatedasafunctionofthreshold.Theresultshowshigherclustercoefficientintheattentionstatethanintheeyes-openstateinallthreebands,suggestingthatclustercoefficientreflectsbrainstate.Inaddition,anobviousfronto-parietalnetworkisfoundintheattentionstate,whichisawell-knownattentionnetwork.Theseresultsindicatethatattentionmodulatesthefronto-parietalconnectivityindifferentmodesascomparedwiththeeyes-openstate.Takentogetherthismethodisanobjectiveandimportanttooltostudythepropertiesofneuralnetworksofbrainrhythm.