Objective To explore the correlation between recurrent respiratory tract infections(RRTI) and immunoglobulin and IgG subtypes in children. Methods According to diagnostic criteria of RRTI,80 cases of children group and 60 cases of control group of different age diagnosed with RRTI were collected from March 2014 to March 2015,and the levels of immunoglobulin (IgG,IgA,IgM)and IgG subtypes (G1,G2,G3,G4) in serum were detected. Results Compared with normal group:in 0 to 2 years old children group,the levels of IgG,IgA and IgM had no obvious differences (P>0.05),the level of IgG4 decreased significantly (P<0.05);In 3 to 5 years old children group,the levels of IgG and IgM had no significant differences (P>0.05),the level of IgA decreased obviously (P<0.05),the levels of IgG2 and IgG4 decreased significantly (P<0.05);In 6 to 12 years old children group,the levels of IgG,IgA and IgM had no obvious differences (P>0.05),the levels of IgG1,IgG2,IgG3 and IgG4 had no significant differences (P>0.05).And as children age,the levels of IgG and IgA had obvious growth trend,the level of IgM changed little.There were defects of IgG subtypes in children with RRTI,the detection rate of 42.5%,individual defects was given priority to with IgG4 accounted for 35%,joint defect was given priority to with IgG2 and IgG4 accounted for 41%. Conclusions There are defects of immunoglobulin IgG subtypes in RRTI of children.The class testing of IgG subtypes should be attached in clinical,the defects in IgG2 and IgG4 may be one of the causes of RRTI in children,which is more sensitive to reflect the immune function of children with RRTI.