〔Abstract〕 Objective To characterize the genetic and functional heterogeneity of peripheral blood mononuclear cells(PBMC) in Takayasu arteritis(TAK) based on single cell nuclear transcriptome sequencing(snRNA-seq) technology and to elucidate the immune mechanisms that may be involved. Methods A total of 6 PBMC specimens were collected from patients who were diagnosed with TAK and had not received drug treatment recently and were admitted to the Second Affiliated Hospital of Anhui Medical University and the Second Affiliated Hospital of Wannan Medical College as the disease group(TAK group). During the same period, PBMC specimens were collected from patients who visited the hospital′s physical examination center. Six cases of PBMC in the population were in the normal group(NC group). Based on the snRNA-seq workflow, library construction and sequencing were performed, and R3.6.2 software was used to carry out PCA and tSNE analysis on the off-machine data from the two groups of PBMC sample pools for detection of gene expression in mononuclear cells. Results The relative proportion and content of immune cells in PBMC of TAK patients had changed; highly cloned TCR could match the amino acid sequence of integrin beta-3 with high homology; T cell-mediated interferon gamma and TNFα pathways were significantly up-regulated. The proportion of TNFRSF13B+ memory B cells increased significantly.Monocytes consistently formed the largest number of ligand-receptor interactions of all cell types. Conclusion During the occurrence and development of TAK, PBMC are involved in complex regulation, and a variety of immune and inflammatory factors are abnormally expressed, among which monocytes play an important role in the interaction of PBMC.