Objective:To study the standardized skill and feasibility of breastconserving assisted by mastoscopy and entirely mastoscopic axillary lymph node dissection. Methods:The clinical results and operation experiences between 276 cases of breastconserving surgery combined with mastoscopic axillary lymph node dissection and 142 cases of modified radical operation in the treatment of breast cancer were analyzed and compared.All the cases were admitted between August 2001 and August 2007 in Beijing Fuxing Hospital,Capital University of Medical Sciences. Results:In 276 cases of breastconserving surgery combined with mastoscopic lymph nodes dissection,the operation time was shortened from 2h originally to 40 min.The shortterm complications were appeared only in 2 cases.In 142 cases of modified radical operation of breast cancer,the shortterm complication were appeared in 27 cases. Conclusion:Using the mastoscopy in the breastconserving surgery combined with traditional axillary lymph node dissection can shorten the operation time and simplify the operation procedure.The method makes patients attain a physiological and psychological minimal invasiveness.Besides assuring the quality of axillary lymph node dissection,the method can reduce the occurrence of surgical complication and improve the patients’ life quality.Mastoscopic axillary lymph node dissection can replace the routine surgery and can be carried out in the conditional hospital.