Objective：To evaluate the expression and localization of Krüppel-like factor 8（KLF8） in human villous tissues during ear－ly pregnancy and to explore the effect of KLF8 on trophoblast invasion during early pregnancy. Methods：A total of 22 early pregnan－cy human villous tissues of 6-11 weeks of gestation（weeks） were obtained from elective terminations of apparently normal pregnancies from March 2012 to June 2012 in The First Affiliated Hospital of Chongqing Medical University. And then immunohistochemical SP method was employed to detect the localization of KLF8 protein. KLF8 mRNA level was determined by quantitative real-time PCR technique and Western blot analysis was used to quantify KLF8 and matrix metalloproteinase-9（MMP-9） protein expression levels.Results：（1）There were KLF8 immunoreactivity expressed in villous tissues from 6-11 weeks. It was primarily located in cyto-and syn－cytio-trophoblast in the trophoblast layer of the chorionic villi. （2）KLF8 mRNA levels were gradually increased with gestational ages，peaked at 8-10 gestational ages（being the highest at 8 weeks） and then decreased sharply. （3）KLF8 and MMP-9 protein levels also shared the same pattern of expression in human villous tissues from early pregnancy：gradually increased from 6 weeks，peaked at 8-10 weeks（being the highest at 8 weeks） and then slightly decreased at the end of the first trimester（11 weeks）. （4）There was a posi－tive correlation between the expression of KLF8 and MMP-9 protein in human villous tissues from early pregnancy（r=0.66，P<0.001）. Conclusions：KLF8 immunoreactivity is primarily located in trophoblast layer especially in the invasion-related cyto-trophoblast cells. Besides，its expression has a forward association with MMP-9 levels and trophoblast invasion. These results indicate that KLF8 may play an important role in the regulation of trophoblast invasion during implantation and placentation.