Inoculationwith arbuscular mycorrhizal(AM)fungi under substrate sterilization conditions can promote plantgrowth，but inoculation with AM fungi under non-sterilization conditions is rarely reported.Therefore，this study studied theeffects of different substratetreatments(sterilized andunsterilized)and inoculation with AM fungi on the root mycorrhizal infectionrate，plantheight，stemdiameter，leafnumber，biomass and root characters of Citrus Junossieb ex Tanaka in greenhouse pot. To investigate whether the Inoculation effect of AM fungi inoculated under simulated natural conditions(substrate not sterilized)was still effective. The results showthat:Under the substrate sterilizationcondition，plantheight， leafnumber，aboveground dryweight，biomass and root traits of Redeckera fulvum(R.f)inoculated were significantly better than those of uninoculated mycorrhizal treatment.Plantheight，stemdiameter，leaf number and biomass of excavata Acaulospora excavata(A.e)were lower after inoculation than those ofexcavata(A.e)withoutinoculation，but there was no significant difference. The root characters were significantly better than the control. The total root length of inoculated R.f was significantly higher than thatof uninoculated R.f，but the other indexes were not significantly different from those of uninoculated R.f. This indicated that inoculation with R.f could improve the growth of orange rootstocks under substratesterilizationconditions，while inoculation with A.e could inhibit the growth of orange rootstocks.However，inoculation with two AM fungi had no significant effect on the growth of orange rootstocks under non-substrate sterilizationconditions，and did not show the same inoculation effect under substrate sterilization conditions.