Abstract: Objective To investigate the presence and distribution of toll-like receptors 3(TL R3)in term human placenta from normal and HBsAg-positive pregnant women and to explore the role of TL R3 in placenta HBV infection.Methods TL R3 and HBsAg in placentas of 19 normal and 102 HBsAg-positive pregnant women were detected by immunohistochemistry SABC.Results The positive rate of TL R3 in normal pregnant women was 100.00% (19/19)and 74.51% (76/102) in HBsAg-positive pregnant women;33 of 102 placentas were infected by HBsAg;There was statistical difference in distribution of TL R3 between placentas of normal and HBsAg-positive pregnant women(χ²=6.17,P=0.012);the relationship between TL R3 and HBV infection was significant(χ²=13.581,P<0.000 1).Conclusion TL R3 is a protect factor of HBV infection in placentas(OR=0.180,0,069-01.69).