Objective To study the effect and mechanism of low molecular weight heparin (LMWH) on endometrial receptivity.Methods The blastocyst implantation failure model was established via mifepristone, and C57BL/6 mice were randomly divided into control group, model group, low-dose LMWH model group and high-dose LMWH model group. The number of embryos on the fifth day of gestation was counted. HE staining was used to compare endometrial glands and blood vessels in each group, and qRT-PCR was applied to detect mRNA levels of platelet endothelial cell adhesion molecule 1 (PECAM1), homeobox A10 (HOXA10), Wnt family member 7A (WNT7A) and beta-catenin.Results Compared with the model group, the number of embryos was increased in the low-dose LMWH model group and high-dose LMWH model group and was even greater in the high-dose LMWH model group (P < 0.05). Besides, the number of embryos in the high-dose LMWH model group was also greater than that in the control group (P < 0.05). The number of endometrial glands and blood vessels in the low-dose LMWH model group and high-dose LMWH model group was greater than that in the model group (P < 0.05), but was not different compared with that in the control group (P > 0.05). In addition, mRNA expression levels of PECAM1, HOXA10, WNT7A and beta-catenin in the low-dose LMWH model group and high-dose LMWH model group were higher compared with the model group (P < 0.05).Conclusions LMWH improves endometrial receptivity through WNT pathway, and its mechanism may be related to PECAM1.