This study was aimed to investigate the therapeutic efficacy of rabbit anti-thymocyte globulin (r-ATG) combined with cyclosporine A (CsA) and to analyse the efficacy-related factors in children with aplastic anemia (AA). Twenty five AA children treated with r-ATG [3.5 mg/(kg·d)×5 days] combined with CsA were analyzed retrospectively. The lymphocyte subgroups, CD4(+)/CD8 ratio and expression of CD55, CD59 on surface of neutrophils and erythrocytes in peripheral blood were detected by direct immunofluorescence method and flow cytometry; the responsive time, effective rate, adverse effects and infections after immunosuppressive therapy (IST) were analyzed; the distribution of T-lymphocyte subgroups in IST-effective and IST-uneffective groups was compared, and therapeutic efficacy-related factors were evaluated. The results showed that the response to treatments was found in 21 out of 25 cases, the total responsive rate was 84.0%; the response time was 3 - 6 months, average of 4 months; the effective rates in month 3, 6, 9, 12 after treatment were 56.0%, 72.0%, 80.0% and 84.0% respectively. The AA children with age ≥ 5 years old, course of disease < 6 months and absolute neutrophil value ≥ 1.5 ×10(9)/L on 30 days after IST had good curative effect; the effective rate in AA children with age ≥ 5 years old, course of disease < 6 months, high or reverse ratio of CD4(+)/CD8(+) and absolute neutrophil value ≥ 1.5×10(9)/L after IST was higher than that in AA children with age < 5 years old, course of disease ≥ 6 months, normal ratio of CD4(+)/CD8(+) and absolute neutrophil value after IST < 1.5×10(9)/L (94.4% vs 57.1%, 90.4% vs 50.0%, 94.1% vs 62.5%, 94.1% vs 62.5%) (P < 0.05). The high effective rate was observed in AA children with decrease of CD55 and CD59 expression, but there was no significant difference (P > 0.05) as compared with normal expression of CD55, CD59. It is concluded that the treatment using r-ATG (3.5 mg/kg·d × 5 d) combined with CsA is a safe and effective for children with AA. Age, course of disease and absolute neutrophil value on 30 days after IST are the main factors affecting curative affect.