Anincubationstudywasperformedtoelucidateexogenousrareearthelements(RE)influencingonmicrobialbiomass,microbialecophysiologicalparameterscmic/corg,metabolicquotientqCO2andrespiratoryrateinrelationtotemporalavailabilityinpaddysoil.Sixsampleswereaddeddifferentconcentrationsbetween0and2000mg*kg-1REEsinsoil.ResultsshowthatexogenousREhaveslightstimulativeeffectsonmicrobialindicesinpaddysoilatlowconcentrationintheearlystageafteraddingRE,whilehavinginhibitoryeffectsathighconcentration.TheinhibitionisstrengthenedwithincreasingREconcentrationandisweakenedwithincreasingincubationtime.PrincipalcomponentanalysisoftheBIOLOGdataindicatesthatmicrobialcommunitystructureshavechanged,carbonsourcesconsumptionofmicroorganismsinpaddysoilbecomesmuchmorerapidafter8weeks,andunderREstress,thechangeofmicrobialcommunitystructuresisalong-termeffect.