To study the diversity and difference of rhizosphere microorganisms of Dendrobium nobile with different epiphytic substrates under the same cultivation environment,in order to clarify the influence of substrates on its rhizosphere microorganisms.The 16S and ITS sequencing of rhizosphere microorganisms of D. nobile in five epiphytic substrates,including stone and wood,using high flux sequencing technology.The diversity and difference of D. nobile rhizosphere microorganisms were compared by combining OTU analysis,Alpha diversity analysis and principal component analysis.A total of 56 phyla,112 classes,275 orders,377 families,and 621 genera of bacteria have been identified;Fungi:13 phyla,47 classes,123 orders,273 families,503 species.The dominant genus of D. nobile fungi in the stone matrix is unidentified_ Cantharellales_ Sp bacteria;the dominant bacteria are Sphingomonas,Fecal bacilli,and unidentified_ Chloroplast;The dominant fungus genus of D. nobile in wood matrix is unidentified_ Cantharellales_ Sp bacteria,Entoloma,the dominant bacteria is Faecalibacterium.The relative abundance of D. nobile in the stone stroma was significantly different from that in the wood stroma,and the dominant genuses were different.The function prediction analysis showed that the epiphytic matrix was closely related to the function of D. nobile rhizosphere microbial community.The difference of rhizosphere microorganisms in different epiphytic substrates of D. nobile may affect the composition of its mycorrhizal fungi,thereby affecting the formation of quality differences in D. nobile.This study provides an experimental basis for the correlation of "substrate-rhizosphere microorganisms-mycorrhizal fungi" of D. nobile,its growth and development,and the accumulation of secondary metabolites,as well as the basis for"the Dendrobium grown on the stone has the superior quality" of D. nobile and the reasonable selection of cultivation substrate of D. nobile.