Abstract: Objective To explore the changes of helper T lymphocytes 17 (Th17) and regulatory T lymphocytes (Tregs) in peripheral blood of patients with extensive burn at early stage in August 2nd aluminum dust explosion accident in Kunshan factory (hereinafter referred to as Kunshan explosion accident) and the significance. Methods Twenty patients with extensive burn in Kunshan explosion accident admitted to our department of burns and plastic surgery were enrolled in burn group, and 10 healthy adult volunteers with no history of smoking were enrolled in healthy control group. Five mL of peripheral venous blood samples were collected from patients in burn group at admission (≤post injury hour 6, PIH 6) and PIH 24, and on post injury day (PID) 7, and from volunteers in healthy control group respectively. The percentages of CD64⁺ T lymphocytes, human leukocyte antigen-DR positive (HLA-DR⁺ ) T lymphocytes, CD3⁺ CD8^- Th17, and CD4⁺ CD25⁺ Tregs in peripheral blood T lymphocytes were determined by flow cytometer. Results (1) The percentages of CD64⁺ T lymphocytes in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(2.35±0.32)% and (4.02±0.15)%] were higher than (0.67±0.11)% of healthy volunteers in healthy control group. The percentage of CD64⁺ T lymphocytes in peripheral blood T lymphocytes of patients in burn group on PID 7 [(0.39±0.25)% ] was lower than that of healthy volunteers in healthy control group. The percentages of HLA-DR⁺ T lymphocytes in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(54±18)% and (72±17)%] were higher than (38±14)% of healthy volunteers in healthy control group. The percentage of HLA-DR⁺ T lymphocytes in peripheral blood T lymphocytes of patients in burn group on PID 7 [(28±15)% ] was lower than that of healthy volunteers in healthy control group. (2) The percentages of CD3⁺ CD8^-Th17 in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24 [(4.21±0.46)% and (7.38±0.39)%] were higher than (0.98±0.09)% of healthy volunteers in healthy control group. The percentage of CD3⁺ CD8^-Th17 in peripheral blood T lymphocytes of patients in burn group on PID 7 [(0.81±0.05)% ] was lower than that of healthy volunteers in healthy control group. (3) The percentages of CD4⁺ CD25⁺ Tregs in peripheral blood T lymphocytes of patients in burn group at admission and PIH 24, and on PID 7 [(1.78±0.26)%, (1.26±0.37)%, and (0.38±0.03)%] were lower than (3.24±0.52)% of healthy volunteers in healthy control group. Conclusions The percentage of Th17 in peripheral blood T lymphocytes of patients with extensive burn at early stage in Kunshan explosion accident increased at first and then decreased compared with that of healthy volunteers, indicating that the patients′ immune function increased first and then weakened. The percentages of Tregs in peripheral blood T lymphocytes at each time point were lower than the percentage of healthy volunteers, indicating that the patients′ immunomodulation gradually weakened after extensive burns.