Abstract: Objective To summarize the immune characteristics in hand foot and mouth disease (HFMD) children with regards to peripheral blood T lymphocyte, B lymphocyte, NK cell and NKT cell, and to discuss its mechanism in the development of HFMD and their detection and clinical value. Methods By means of flow cytometry, 152 children with HFMD and 45 healthy children were detected for the percentage of T lymphocyte, B lymphocyte, NK cell, NKT cell in peripheral blood. Results The percentage of CD₃⁺,CD₃⁺ CD₄⁺, CD₃⁺ CD₈⁺, NK cells and ratio of CD₄⁺/CD₈⁺ of HFMD acute phase group were lower than those in healthy group, while NKT cells, B cells were higher. The percentage of CD₃⁺, CD₃⁺ CD₄⁺, CD₃⁺ CD₈⁺, NKT cells and CD₄⁺/CD₈⁺ ratio of HFMD acute phase were lower than those of recovery phase, while B cells and NK cells were higher. The percentage of CD₃⁺ cells, CD₃⁺ CD₄⁺ cells, CD₃⁺ CD₈⁺ cells, NKT cells and the ratio of CD₄⁺/CD₈⁺ in severe HFMD group were lower than those in mild group, while B cells and NK cells were higher. Conclusion The immune function of children with HFMD proved disordered; CD₃⁺ cells, CD₃⁺ CD₄⁺ cells and B cells in peripheral lymphocytes were increased during the acute phase of HFMD;NKT cells increased during recovery phase of HFMD.We conclude that lymphocyte subsets detection can be used as an index of prognosis of HFMD in children.