Objective To investigate the clinical efficacy of high-dose Gamma Globulin combined with Dexamethasone in the treatment of children with immunologic thrombocytopenic purpura (ITP). Methods A total of 71 children with ITP admitted to Hubei Provincial Geological Staff Hospital from January 2019 to January 2021 were selected as the research objects, and the patients were divided into the observation group (n=36, the number is an odd number) and the control group (n=35, the number is an even number). The control group was treated with Dexamethasone, and the observation group was treated with high-dose Gamma Globulin on the basis of the control group. The clinical efficacy of the two groups after treatment and the expression levels of CD3+, CD4+CD25+Treg in the two groups before and after treatment were compared. At the same time, the platelet count, the peak time of platelet count and the length of hospital stay were recorded in the two groups before and after treatment. Results The total effective rate of the observation group after treatment was significantly higher than that of the control group, the difference was statistically significant(P＜0.05). The CD3+and CD4+CD25+Treg of the observation group after treatment were significantly higher than those of the control group, the differences were statistically significant (P＜0.05). The platelet count of the observation group after treatment was higher than that of the control group, and the peak time of platelet count and the time of hospitalization in the observation group were significantly shorter than those in the control group, the differences were statistically significant (P＜0.05). Conclusion Dexamethasone combined with high-dose Gamma Globulin can improve the therapeutic effect of children with ITP, and can adjust the body′s immune function indexes, shorten the peak time of platelet count,increase platelet count, and shorten the hospital stay of children.