To study the association between MICA allelic polymorphism and susceptibility to HBV infection in Hainan population. Polymorphism of MICA alleles in samples was detected by PCR-SSP and PCR method. A total of 10 MICA alleles and 5 MICA-STR alleles were detected in HBV infected patients. Compared with the control group, MICA 010 and MICA-A5 allele may be susceptible to HBV infection.For MICA*010:OR=3.88, 95%CI:2.19~6.85, P=0.000, MICA-A5: OR=1.27, 95%CI: 0.92~1.77, P=0.0068. MICA*008 / 045 genotype may not be susceptible to HBV infection, and MICA 010/010 homozygous genotype may be susceptible to HBV infection.For MICA* 008/045: OR=0.09, 95%CI: 0.01~1.74, P=0.0071; For MICA*010/010:OR=4.41, 95%CI: 1.26~15.46, P=0.0106. MICA allelic polymorphism was associated with susceptibility to HBV infection in Hainan population.