Objective:To establish a model of human breast carcinoma in ovariectomized nude mice and study their biological features. Methods:MCF-7 cells(estrogen-receptor positive,ER+) were implanted into the flank of ovariectomized nude mice. The tumor was stimulated by estradiol E2 transdermal patches. Tumor size and body weight were monitored weekly during the study. The tumor-bearing mice were killed on day 30 and tumor masses were collected for analysis. Tumor tissues were pathologically examined by the light microscope. The ER protein was detected by immunohistochemistry. Results:The tumor tubercles could be formed on day 4. The tumor-take rate was 75%(12/16),and the mean tumor surface areas was(10.0 ± 2.1)mm2. All of the specimens were infiltrating ductal carcinoma,and ER expression was positive. Conclusion:Human breast carcinoma model was established successfully in ovariectomized nude mice,which reserved certain biological features of human breast carcinoma,and it was convenient to use transdermal patches,therefore it might be an available model for further research on breast carcinoma.