Arctium lappa L. is widely used for medicinal purposes across China, and significant effort has been directed toward enhancing its quality. Association with microorganisms has been shown to influence both plant growth and metabolites, providing a possible avenue for its quality improvement. In this study, we investigated the microorganism compositions of the root, stem, leaf, fruit and rhizospheric soil of A. lappa through high-throughput Illumina sequencing of 16S rRNA genes and ITS regions. A total of 796,891 16S rRNA and 626,270 ITS reads were obtained from the samples. Analysis of the sequencing data revealed that bacterial and fungal communities were more diverse in the rhizospheric soil sample compared with other samples. Cyanobacteria, Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes phyla were found in all samples. Cyanobacteria was particularly enriched in the root, stem, leaf and fruit at 88.59%, 86.15%, 98.31% and 93.57%, respectively; Actinobacteria was the highest in rhizospheric soil, at 37.53%. Ascomycota was the most dominant fungal phylum, representing 69.17%, 58.18%, 87.93%, 90.18% and 80.21% in the root, stem, leaf, fruit, and rhizospheric soil, respectively. Several novel unclassifiable bacterial and fungal species were also detected. In total, we detected about 922 bacterial and 334 fungal species, which include a number of unclassifiable species. Additionally, the root, stem, leaf, fruit and rhizospheric soil of A. lappa were sources for screening new bioactive metabolites.