Abstract: OBJECTIVE To explore the clinical significance of the changes of trace elements and erythrocyte immune function for the diagnosis of preschool children with recurrent respiratory tract infections,so as to provide reference for relevant research of recurrent respiratory tract infections.METHODS A total of 44 cases of children with recurrent respiratory tract infections from Dec.2010 to Dec.2013 were chosen as the study group,while 44 cases of healthy children at the same period had examination were as the control group.The immune index cell(CD₃⁺,CD₄⁺,CD₂₅⁺,CD₄⁺),red blood cell immunity index（ATER,FEER and DYER）and trace indicators（Zn⁺,Ca⁺and Cu⁺）and other levels were observed and compared.RESULTS The CD₃⁺,CD₄⁺,CD₂₅⁺and CD₄⁺index levels of the study group were（56.54 ± 4.56）%,（15.43 ± 1.45）% and（35.45 ± 4.32）%,significancely lower than the control group of（70.34 ± 5.46）%,（23.45 ± 2.35）% and（47.35 ± 5.43）%（P＜0.05）.The index levels of Zn⁺and Ca⁺in study group were（33.87±4.30）μmol/L and（1.32±0.21）mmol/L,significancely lower than control group,and Cu⁺ was（15.32±2.19）mmol/L,significancely higher than control group（P＜0.05）.CONCLUSION Recurrent respiratory tract infections can lead to the decreasing of immune parameters,erythrocyte immunity relative indexes,and the abnormal of trace element related indicators in the preschool children.Therefore the monitoring of these indicators can help to prevent and treatment of disease.