Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies among fertile women. PCOS patients have been confirmed to be accompanied by an increased risk of pregnancy complication, and the exact cause is still unclear. Many factors may cause this situation, and impaired endometrial receptivity could be responsible for adverse pregnancy outcomes in PCOS. Unfortunately, there were still few researches about the molecular mechanisms regarding impaired endometrial receptivity. So we designed this study to explore the secretory endometrial proteome in PCOS patients.