Abstract: ObjectiveTo study the association between HLA-DR3,DR7,DR13,DR53 and HBV intrauterine infection to probe into the susceptibility to intrauterine infection of hepatitis Bvirus and to find its predisposing genes and protecting genes.MethodHLA-DR3,DR7,DR13,DR53 were detected by the technique of poly merase chain reaction-sequence specific primers(PCR-SSP)in maternal and neonatal blood clot.Results(1)The frequency of HLA-DR was 24.14% in women with intrauterine infection,which was higher than that(6.33%)in women without intrauterine infection(P=0.007).There was no association between HLA-DR7,DR 13,DR53 positive in pregnant women and HBVintr auterine infection(P>0.05).(2)The frequeney of HLA-R of new borns was 17.24% in women with intrauterine infection,which is higher that(5.06%)in women withotll infection(P=0.033).There was no association between HLA-DR7,DR13,DR53 positive in new borns and HBVintrauterine infection(P>0.05).(3)There was significant association between HLA-DR3 concordance and HBV intrauterine infection(P=0.049).There was no association between DR7,DR13,DR53 conco rdance and HBV intrauterine infection(P>0.05).ConclusionHLA-DR3 carriers of pregnant women and their new borns have susceptibility to HBV intrauterine infection.HLA-DR3 is the predisposing gene of HBV intrauterine infection.