Abstract: Objective To observe the mid-term effect,safety and cosmetic effect of breast-conserving surgery combined with intraoperative radiotherapy (IORT) on early breast cancer. Methods Clinical data about 63 early breast cancer patients who underwent breast-conserving surgery combined with IORT in the First Medical Center of Chinese PLA General Hospital from November 2008 to March 2012 were retrospectively analyzed.The adverse reactions,outcomes and cosmetic effect were evaluated during follow-up.Results By March 2019,the median follow-up time was 102 months (range,80-120 months),with the overall survival rate of 98.4% (62/63) and the disease-free survival rate of 90.5% (57/63).In terms of adverse events,7 patients (11.1%,7/63) developed grade I radiation-induced pulmonary injury,and 10 patients (15.9%,10/63) had radiation fibrosis in the surgical site,5 patients (7.9%,5/63) had skin color changes,16 patients (25.4%,16/63) had surgical site pain.In terms of cosmetic effects,excellent cosmetic effect was achieved in 48 cases (78.7%) and good effect in 13 cases (21.3%).There was no significant correlation between the incidence of radiation-induced lung injury,cosmetic effects,and intraoperative radiotherapy dose (P>0.05). Conclusion The curative effect and cosmetic effect of breast-conserving surgery combined with intraoperative radiotherapy for early breast cancer are good,without any serious adverse reactions.