Background and Objective: Young women with polycystic ovary syndrome (PCOS) have a high risk of developing endometrial carcinoma. There is a need for the development of new medical therapies that can reduce the need for surgical intervention so as to preserve the fertility of these patients. This study which was studied retrospectively aimed to explore the clinical efficacy and safety of hysteroscopy in the treatment of endometrial dysplasia or early endometrioid adenocarcinoma in young patients with PCOS and IR. Methods: the patients were divided into 2 groups, 1) The group of drug treatment: a total of 11 cases (9 cases of EAH, 2 cases of EEC), by Diane -35(1 tablets per day ,for 21 days one month) combined with metforminï¼ˆ1000mg,q dï¼‰ in the treatment, every 3 months by curettage + pathological evaluation; 2)hysteroscopic treatment group: a total of 32 cases (21 cases of EAH, 11 cases of EEC) by using of Diane-35 combined with metformin, every 3 months by hysteroscopic surgery under the lesion excision and curettage + pathological evaluation. Results: All patients were pathologically confirmed that endometrial lesions were successfully reversed, atypical endometrial hyperplasia of the patients in group of drug treatment was successfully reversed in 6.58 + 3.11 months; atypical endometrial hyperplasia of the patients in hysteroscopy treatment group were successfully reversed in 4.1 + 1.30 months, the difference was statistically significant (p=0.025); early endometrial adenocarcinoma of the patients in group of drug treatment successfully reversed in 6.9 + 1.34 months; early endometrial adenocarcinoma of the patients in hysteroscopy treatment group were successfully reversed in 4.7 - 1.73 months, the difference was statistically significant (p=0.018); pregnancy outcomes: s in group of drug treatment: 2 cases of full-term delivery in EAH, of 2 with natural conception; in hysteroscopy treatment group , 6 cases (4 cases of EEC, 2 cases of EAH) of full-term delivery, another 3 cases are still in pregnancy. Conclusion: The drug treatment of Diane -35 combined with metformin can completely reverse endometrial precancerous lesion and early endometrial adenocarcinoma of PCOS with IR, Hysteroscopy, which could radically resect endometrial lesions, can achieve th goal of " Disease-free ", so it can significantly shorten shorten the therapeutic time of drugs (p < 0.05).