In recent years, the incidence of ovarian malignant tumor is increasing year by year and the patients tend to be younger. Typically, epithelial ovarian cancer often has no obvious symptoms and no effective monitoring means in the early stage, and is usually diagnosed in the late stage with poor prognosis. Even with standard surgery and chemotherapy, the 5-year survival rate of advanced epithelial ovarian cancer is 20%–30%, while the 5-year survival rate of early epithelial ovarian cancer (I–II) patients is 90%. The survival rate of epithelial ovarian cancer is related with its stage and treatment effect. Clinically, an effective monitoring method has been explored for early diagnose and accurate evaluation of the treatment effect of advanced epithelial ovarian cancer, so as to improve the survival rate of patients. As a new tumor marker in recent years, human epididymis protein 4 (HE4) has a limited expression in normal tissues, a low expression level in benign tumors, and a high expression level in epithelial ovarian cancer tissues and serum. Many studies have shown that HE4 has a certain value in the diagnosis, treatment, and prognosis of early epithelial ovarian cancer.