Objective To investigate the changes and clinical significance of peripheral blood mucosal-associated invariant T (MAIT) cells in children with influenza. Methods Children with influenza who received treatment in the outpatient and inpatient departments of a children's hospital from January to May 2023 were selected and divided into the common type group and the severe type group. Healthy children who underwent physical examination in this hospital during the same period were selected as the healthy control group. Within 24 hours after admission, children's venous blood was drawn for testing; ratios of MAIT cells (CD3⁺CD161⁺TCRVα7.2⁺cells)and MAIT cells expressing PD-1, CD69, perforin, and CD107 α were tested by flow cytometry, respectively. Differences among all the groups were compared. Results Compared with the control group, the proportion of peripheral blood MAIT cells in children with common and severe influenza gradually decreased, while the proportion of CD69-expressing and perforin-positive MAIT cells increased gradually. Differences were statistically significant (all P < 0.05). There was no statistically significant difference in the proportion of MAIT cells expressing CD107 (P>0.05). The proportion of PD-1 positive MAIT cells increased (P < 0.05), but there was no statistically significant difference between the common type and severe type groups (P>0.05). Conclusion The decrease of peripheral blood MAIT cells accompanied with immune activation plays a role in the pathogenesis of influenza.