The incidence of endometrial cancer among Chinese women has increased year by year with a younger trend in morbidity age. Young patients with early endometrial cancer are increasingly demanding fertility preservation. At present, progesterone therapy is still the first choice of fertility-sparing treatment, and has achieved good results. However, progesterone resistance and adverse reactions have also become the main reasons for the failure of progesterone therapy in some patients. Therefore, understanding the mechanism of progesterone resistance and exploring coping methods has guiding significance in the fertility-sparing treatment for early endometrial cancer patients. This article reviews the mechanism of progesterone resistance, the new treatment methods to solve progesterone resistance (such as hysteroscopy), and the significance of molecular typing of endometrial cancer in predicting progesterone resistance.