The purpose of this study was to observe the alterations of endometrial receptivity in the rats with ovarian hyperstimulation syndrome (OHSS) and determine whether OHSS is favorable for the embryo implantation.OHSS model was developed in clean Wistar rats (gender: female; age: 21 days).A total of 60 rats were divided into 3 groups (with 20 rats in each group): hyperstimulation group, regular stimulation group and control group.