Background: The number of patients receiving anaesthesia is increasing, but the impact of general anaesthesia on the patient's immune system remains unclear. The aim of the present study is to investigate dynamics of systemic immune cell responses to anaesthesia during perioperative period at a single-cell solution. Methods: The peripheral blood mononuclear cells (PBMCs) and clinical phenomes were harvested and recorded 1 day before anaesthesia and operation, just after anaesthesia (0 h), and 24 and 48 h after anaesthesia. Single-cell sequencing of PBMCs was performed with 10× genomics. Subsequently, data analysis was performed with R packages: Seurat, clusterProfiler and CellPhoneDB. Results: We found that the cluster of CD56+ NK cells changed at 0 h and the cluster of monocytes increased at 24 and 48 h after anaesthesia. The characteristic genes of CD56+ NK cells were mainly enriched in the Jak-STAT signalling pathway and in cell adhesion molecules (24 h) and carbon metabolism (48 h). The communication between CD14+ monocytes and other cells decreased substantially 0 and 48 h after operation. The number of plasma cells enriched in protein export in men was substantially higher than that in women, although the total number in patients decreased 24 h after operation. CD14+ monocytes dominated that cell-cell communications appeared in females, while CD8+ NKT cells dominated that cell-cell communications appeared in male. The number of plasma cells increased substantially in patients with major surgical trauma, with enrichments of pentose phosphate pathway. The communications between plasma cells with other cells varied between surgical severities and anaesthetic forms. The intravenous anaesthesia caused major alterations of cell types, including CD14+ monocytes, plasmas cells and MAIT cells, as compared with inhalation anaesthesia. Conclusion: We initially reported the roles of perioperative anaesthesia/surgery in temporal phenomes of circulating immune cells at a single-cell solution. Thus, the protection against immune cell changes would benefit the recovery from anaesthesia/surgery. Keywords: PBMCs; anaesthesia; perioperation; scRNA-seq.