Abstract: Objective To investigate the immunohistochemical expression and its clinical significance of telomerase, MUC1 and STAT6 of atypical endometrial hyperplasia in carcinogenesis.Methods A total of the surgery and curettage specimens of 220 cases were collected. Among the 220 cases, 40 cases were normal endometrium, endometrial mild, moderate and severe atypical hyperplasia was 40 cases, respectively, and 60 cases were uterus endometrioid carcinoma. Immunohistochemical detection method was used to detect the expression of telomerase, MUC1 and STAT6 in the samples. The expression rule and the characteristics of each group were summarized.Results The expressions of the telomerase, MUC1 and STAT6 in the samples of endometrial adenocarcinoma and atypical hyperplasia were significantly higher than that of the normal endometrium. There were significant differences (P< 0.05). The expressions of telomerase and MUC1 in the samples of endometrial adenocarcinoma were significantly higher than that of mild and moderate dysplasia. There were significant differences (P< 0.05). The difference in the expression of telomerase between the severe and mild atypical hyperplasia was statistically significant (P< 0.05). However, there was no difference in the expression of STAT6 between different atypical hyperplasia and endometrioid adenocarcinoma (P> 0.05). There was no difference in the expressions of telomerase, MUC1 and STAT6 between severe atypical hyperplasia and endometrioid adenocarcinoma (P> 0.05).Conclusion The positive expression or positive strengthening of the combination detection of telomerase, MUC1 and STAT6 in the same degree of endometrial hyperplasia indicate that there was a great potential of progression to more severe atypical hyperplasia and cancerization. It has certain guiding significance to the early clinical diagnosis and prognosis.