Objective To analyze and compare the clinical characteristics and therapeutic effects on pediatric patients with immune thrombocytopenia (ITP) among infants and children more than 3 years old.Methods The data of 1 015 ITP children who were hospitalized in West China Secondary Hospital of Sichuan University between January,2005 to January,2012 were collected.All of the patients were given hormone shock treatment and/or intravenous immunoglobulin (IVIG).According to the extent of platelet count and bleeding improvement,the outcome included complete response,response and no response.The patients were divided into the infant group(≤3 year old) and the elderly group (＞3 years old) based on age,acute group(≤6 months) and chronic group(＞6 months) based on the course of disease,their clinic data were retrospectively analyzed by software SPSS 12.0.Results (1) The male/female ratio of infants group was higher than that of the elderly group,and there was significant differences (57.1％ vs 45.3％,x2 =13.927,P ＜ 0.001).(2) The median platelet count on admission in the infant group was statistically higher than that of the elderly group(9 × 109/L vs 8 × 109/L,Z =2.448,P =0.014).The course of disease in the infant group was statistically shorter than that in the elderly group(7 d vs 75 d,Z =13.317,P ＜ 0.001).(3) The increase ratio of megakrocytes in infants group was lower than that in the elderly group,but no statistical differences were found (86.4％ vs 90.4％,x2 =2.534,P =0.111).(4) There was a significant difference in terms of hospital stays between the transfused patients and untransfused patients (6.5 d vs 7.1 d,Z =4.571,P ＜ 0.001).Under the same treatment,the time for the platelets to become normal in the transfused group was statistically lower than that in the non-transfused group (72 h vs 89 h,Z =4.116,P ＜ 0.001).(5)The time needed for the platelets to become normal (≥ 100 × 109/L) in the infant group were statistically lower than that in the elderly group(72 h vs 95 h,Z =6.540,P ＜0.001).(6)The ratio of chronic patients in the infant group was statistically lower than that in the elderly group (3.2％ vs 30.1％,x2 =178.42,P ＜ 0.001).Conclusions The male infants with ITP are more than the female and the course of disease is shorter.The infants' platelet count returns to normal faster,with better treatment efficacy and lower ratio of chronic patients.The hospital stays can be shortened in the patients with ITP who were transfused with platelets,but the course of treatment with hormone can not be shortened.