Abstract: Objective　To analyze the efficacy of different doses of intravenous immunoglobulin (IVIG) in the treatment of acquired severe aplastic anemia (AA) in children. Methods　The clinical data of hospitalized children with severe AA who received adjuvant immunosuppressive therapy of IVIG from January 2000 to December 2015 were retrospectively analyzed. According to different doses of treatment, the children were divided into low dose group ( IVIG 200-400 mg/ (kg·d) once every 4 weeks for 6 times), high dose group (IVIG 1 g/ (kg·d ) x 2 days once every 4 weeks for 6 times). Results　All the children were followed up until December 31, 2015. Among the 61 children, it was effective in 41 children and total effective rate was 67.2%. The effective rate of anti thymocyte globulin (ATG) treatment in high dose group was higher after 3 months than that of low dose group, and there was statistical difference (P=0.020). The interval between first dose of IVIG and first dose of ATG in 20 cases of ineffectiveness was 2.0 (2.0-5.0) d, while that in 41 cases of effectiveness was 8.0 (7.0-9.0) d, and the difference is statistically significant (P<0.001); Among the 20 ineffective children, 18 children had the interval <7 day. The survival rates of the two groups were 80% and 87.1%, respectively, and there was no difference between two groups (P>0.05). The incidence of severe infections in the high-dose group was lower than that in the low-dose group after the use of ATG for 6 months, and there was statistical difference (P=0.008). Conclusions　High dose of IVIG therapy can increase the early response rate in children with acquired severe AA, but it does not increase the long-term effectiveness, cure rate and 5 year survival rate. In addition, it can reduce the severe infection rate, but cannot reduce the total infection rate and infection related mortality rate.