According to the study about the frequency of HLA haplotypes among the Guanzhong Han population, we observed six HLA A-B haplotypes, six HLA B-DRB1 haplotypes, and two HLA A-B-DRB1 haplotypes with frequencies higher than the others [27] and compared their frequencies between HFRS patients and normal controls. The gene discussed is HLA-DRB1; the disease is hemorrhagic fever with renal syndrome.