Abstract: Objective To explore the correction between serum trace elements,peripheral blood T lymphocyte subsets and children with recurrent respiratory tract infection.Methods 66 children with recurrent respiratory tract infection were selected and designed as observation group, and 66 children with health examination were designed as control group.Serum trace elements and peripheral blood T lymphocyte subsets of two groups were compared,and the detection results of observation group with upper respiratory tract infection and lower respiratory tract infection,at the stage of attack and catabasis were compared as well.Results The serum Zn+,Fe3+,Mg2+ and CD3+,CD4+,CD4 /CD8 of observation group were significantly lower than those of control group, while serum Cu2+ and CD8+ were higher than those of control group.Detection results of observa-tion group with lower respiratory tract infection and at the stage of attack were worse than those of children with upper respiratory tract infection and at the stage of catabasis.Serum trace elements and peripheral blood T lymphocyte subsets was closely correlated with the disease (all P <0.05). Conclusion Serum trace elements and peripheral blood T lymphocyte subsets of children with re-current respiratory tract infection are abnormal,and these indexes are closely correlated with the disease.