Objective To investigate the effect of pidotimod granules and Carboxymethyl starch sodium solution in treating children with recurrent respiratory tract infection curative effect and effect on immune function of children.Methods 128 cases of children with recurrent respiratory tract infection in our hospital from June 2013 to June 2016 were selected and divided into treatment group and control group with 64 cases in each group. Children in the control group were treated with Carboxymethyl starch sodium solution, the treatment group was given pidotimod granules on the basis of the control group.Two groups of children were treated for 12 weeks.The therapeutic effects of the two groups were compared, the changes of immune function before and after treatment, cough, fever, lung rales disappear time, and the incidence of adverse reactions.Results The total effective rate of the treatment group (90.62%) was higher than the control group (75.00%), the difference was statistically significant (P<0.05), the levels of IgA, IgM and IgG increased after treatment in both groups, the levels of IgA, IgM and IgG in the treatment group were higher than those in the control group, the difference was statistically significant (P<0.05), the levels of CD3 +, CD4 +and CD4 +/CD8 +increased after treatment in both groups, and the levels of CD3 +, CD4 +and CD4 +/CD8 +in the treatment group were higher than those in the control group, the difference was statistically significant (P<0.05), the treatment group in children with cough, fever, pulmonary rales disappeared faster than the control group, the difference was statistically significant (P <0.05), two groups were no obvious adverse reactions.Conclusion Pidotimod granules combined with carboxymethyl starch sodium solution in treating children with recurrent respiratory tract infections is effective, and could significantly improve the immune function of children.