Abstract: ObjectiveThe effects of different altitudes on soil microbial flora of Amorphophallus konjac and its rela-tionship with the occurrence of soft rot in A.konjac were studied to provide theoretical basis for the development of A.kon-jac industry and the use of soil microbial ecology in controlling A.konjac diseases.MethodThe fungi amount,bacteria amount,actinomycetes amount,microbial biomass and microbial diversity of A.konjac were studied at four altitudes (610,913,1205 and 1518 m)by field experiment at four growth periods(seedling period,seed-new tuber conversion pe-riod,tuber enlargement period and tuber maturation period).The experimental data were analyzed by DPS7.05 data pro-cessing system.ResultIn the same altitude at the same period,as A.konjac grew,soft rot incidence increased then de-clined,and reached the peak at tuber enlargement period.In different altitudes at the same period,as altitude rose,soft rot incidence decreased.With growth and development of A.konjac,bacteria,fungi,actinomycetes and microbial biomass,all presented a down-up variation,which meant seedling period>seed-new tuber conversion period>tuber enlargement period>tuber maturation period.Fungi,bacteria,actinomycetes and microbial biomass of rhizospheric microorganisms all increased with the rising of altitude.Altitude had insignificant difference on diversity of rhizospheric microorganisms (P>0.05).ConclusionThe appropriate increase of altitude of planting area can effectively adjust the rhizosphere micro-bial flora of A.konjac,which is an effective measure to control the occurrence of A.konjac soft rot.