The mechanisms underlying the role of mast cells in wound healing have not been thoroughly studied, and even fewer data are available on studies related to mast cells in the skin of patients with type 2 diabetes mellitus (T2DM). Therefore, this study aims to explore the transcriptional characteristics of mast cells at the single-cell level in patients with T2DM and provide experimental data for studying mast cell behaviors under abnormal glucose metabolism.Two patients with T2DM and one trauma patient without diabetes were enrolled. Samples were derived from skin tissue resected at the time of surgery and were isolated by single cell capture technology on BD platform to prepare single cell cDNA library. Seurat was used to process raw reads and analyze data downstream of single-cell RNA sequencing, including removal of low-quality cells, identification of cell clusters at the single-cell level, and screening for differential genes with fold change > 1.5 and p < 0.05 by two-sided t-test. We performed single-cell RNA sequencing on skin tissues of T2DM patients and non-diabetics and identified the cell cluster of skin, single-cell subsets, and transcriptional characteristics of mast cells at a single-cell level. Meanwhile, gene set enrichment(GSEA) analysis was performed on the differentially expressed genes.A total of 8888 cells were obtained from skin tissue. Clustering analysis revealed eight-cell clusters, identified as smooth muscle cells, dendritic cells, mast cells, and T cells, respectively. Cluster 6 was identified as mast cells with the marker genes TPSAB1, CPA3, TPSB2, MS4A2,KIT, etc., which accounting for 2.7% of the total cell number.Compared with the control group, the genes highly expressed in MCs from T2DM patients, include ADH1C, PAXIP1, HAS1, ARG1, etc., and the low expression genes include PHACTR2, GGA1, RASSF2, etc. GSEA analysis suggested that the signal pathways of MCS in T2DM patients included VEGF signaling pathway, Fc gamma R-mediated phagocytosis, the B cell receptor signaling pathway, natural killer cell-mediated cytotoxicity.The characteristic genes of MCs in the skin tissues of T2DM patients were described at the single-cell level. These genes and enriched signaling pathways provide a theoretical basis and data support for further researches on dermatopathy in patients with diabetes mellitus.Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.