【Objective】 To investigate the transfusion effect of 0.5-dose of apheresis platelet in pediatric patients. 【Methods】 A total of 195 children who underwent 0.5-dose platelet transfusion from August 2021 to June 2022 were enrolled, and the platelet count within 24 hours before and after platelet transfusion were recorded. They were grouped by gender, disease type, blood product transfusion history, platelet antibody results, platelet storage time and weight to analyze the effect of platelet transfusion. 【Results】 Among 195 cases, 77.4% (151/195) were effective and 22.6% (44/195) were ineffective after 0.5-dose of platelet transfusion. Platelet transfusion more than three times has significant impact on the effectiveness of platelet transfusion, with platelet transfusion efficiency decreased from 80.8% to 65.9% (P<0.05), and CCI decreased from 11.56±8.94 to 8.52±8.42 (P<0.05). The transfusion effect of the HLA and HPA antibodies positive group was significantly lower than the negative group, with CCI decreased from 11.39±8.87 to 7.82±8.59 (P=0.05). Linear regression analysis showed that the effect of platelet transfusion decreased with the increasing of platelet storage time (P<0.05), and the effect of platelet transfusion decreased in children weighing less than 20 kg compared with those weighing more than 20 kg, with the effective rate decreased from 84.1% to 63.5% (P<0.05). Different gender, disease type and the number of red blood cell transfusions had no significant effect on platelet transfusion. 【Conclusion】 The 0.5-dose platelet transfusion has good therapeutic effect in children below 20 kg. The results of HLA and HPA antibodies and the number of platelet transfusions greatly influence the effect of platelet transfusion in children, and the transfusion effect decreases with the increase of platelet storage time.