【Objective】 To study the correlation between platelet transfusion efficacy and KIR receptor-HLA ligand. 【Methods】 Thirty-three leukemia patients with positive HLA antibody were tested for cross-matching with donor platelets. Platelets from suitable donors were selected for transfusion, and the 24-hour platelet corrected count increment (CCI) was used to determine the transfusion effect. KIR and ligand genotyping were performed on blood samples from patients and donors by PCR-SSP method, and the relationship between platelet transfusion effects and KIR receptor-HLA ligand was analyzed. 【Results】 In 74 occasions of platelet transfusion, 42 were ineffective and 32 were effective. When the donor had C2 gene and HLA-B Bw4-80T gene, the frequency of ineffective platelet transfusion in the recipient was 69.0% (29/42) and 52.4% (22/35), respectively, which was significantly higher than that in the effective group [25.0% (8/32) and 25.0% (8/32)]. When the donor had C1 gene, and the frequency of effective platelet transfusion in the recipient was 100.0%(32/32), which was higher than that in the ineffective group [83.3%(35/42)]. When the recipient-donor matching mode was KIR2DL1-C2 and KIR3DL1-(HLA-B Bw4-80T), the frequency of ineffective platelet transfusion was 69.0%(29/42) and 40.5%(22/42),higher than that of the effective group [25% (8/32) and 18.8% (6/32)]. When the recipient-donor matching model was KIR2DL3-C1, the rate of effective platelet transfusion in 32 patients (100.0%), which was higher than that (35 patients 83. 3%) in the ineffective group. When the mismatch mode of recipient iKIR+donor HLA ligand receptor was KIR2DL1-C2, the frequency of effective platelet transfusion in the recipient was 78.1% (25/32), which was much higher than that in the ineffective group [31.0% (13/42)]. When the mismatch mode was KIR3DL1-(HLA-B Bw4-80T), the rate of effective platelet transfusion in the recipient was 68.8% (22/32), which was higher than that in the ineffective group (42.9%, 18/42). The difference between the above groups was statistically significant(P<0.05). 【Conclusion】 HLA-C1 and HLA-C2 genes are the key factors affecting the efficacy of platelet transfusion.For platelet refractorines, HLA-C1 is the protective gene, while HLA-C2 and HLA-B Bw4-80T are the susceptible genes. The recipient iKIR+donor HLA ligand receptor model may play an important role in platelet refractoriness.