Objective：To investigate the roles of classic Wnt/β-catenin signaling pathway in the oxidative stress injury of trophoblasts involved in the development of preeclampsia. Methods：（1）Immunohistochemistry and Western blot were utilized to determine the ex－pression of β-catenin in the placental tissues. （2）Cell treatment and classification of each group were as follow：normal culture group，H/R culture group，LiCl+normal culture group，LiCl+H/R culture group. The expressions and localization of β-catenin protein were detected by Western blot and immunofluorescence.（3）Flow cytometry assay was employed to verify the level of reactive oxygen species（ROS） and apoptosis index of HTR8/SVneo. （4）Changes of cell invasion rates were identified by transwell matrigel invasion assay；the activities of matrix metalloproteinase（MMP-2，9） were measured by gelatin zymography assay. Results：（1）The level of β-catenin protein decreased in placental tissues of preeclamptic compared with that in normal third trimester（P<0.05）. （2）In HTR8/SV－neo cells，β-catenin was located in both nucleus and cytoplasm. HTR8/SVneo cells exposed to H/R showed a significant decrease in β-catenin protein levels compared with the normal culture cells（P<0.01）. Pretreated with LiCl could upregulate the expression of β-catenin in H/R cells（P<0.01）. （3）Treatment with H/R could increase the level of ROS and apoptosis，and reduce the inva－sive ability of HTR8/SVneo cells in vitro（P<0.01）. Pretreated with LiCl could inhibit the accumulation of ROS and apoptosis of cells caused by oxidative stress（P<0.01，P<0.05）. （4）The enzymatic activities of MMP-2，9 and the invasion rates of cells in vitro decreased significantly in HTR8/SVneo cells exposed to H/R（P<0.01），while pretreated with LiCl could increase the enzymatic activities of MMP-2，9 and enhance the invasion rates of HTR8/SVneo cells exposed to H/R（P<0.01）. Conclusion：LiCl via activate the classical wnt/β-catenin signaling pathway to inhibit the injury of oxidative stress on trophoblast.