Objective To explore the clinical effect of breast-conserving surgery on young patients with breast cancer. Methods A total of 208 young breast cancer patients (age≤35 years) who were admitted to The Second Affiliated Hospital of Nanchang University from Feb. 2012 to Feb. 2017 were enrolled and divided into breast-conserving group (n=64) and modified radical mastectomy group (control group, n=144). The Mann-Whitney U test was used to analyze the differences in the intraoperative blood loss, postoperative drainage, and hospital stay between the 2 groups. The Kaplan-Meier method was used to analyze the disease-free survival (DFS) of the 2 groups. Univariate and multivariate Cox proportional hazards regression models were used to analyze the effect of breast-conserving therapy on DFS of young breast cancer patients. Results The intraoperative blood loss and postoperative drainage of patients in the breast-conserving group were significantly less than those in the control group (both P＜0.05), and the hospital stay was significantly shorter than that in the control group (P＜0.05). The DFS of the breast-conserving group was significantly shorter than that of the control group (55.3 months vs 58.1 months, P=0.001). Multivariate Cox proportional hazards regression model analysis showed that breast-conserving therapy (hazard ratio [HR］＝3.090, 95% confidence interval[CI］1.498-6.371, P=0.002), histological grading of tumor (Ⅲ) (HR=4.572, 95% CI 1.055-19.813, P=0.042), and triple negative breast cancer (HR=4.302, 95% CI 1.142-16.212, P=0.031) were independent risk factors of DFS in young breast cancer patients. Conclusion Breast-conserving surgery has the advantages of less trauma and shorter hospital stay in young patients with breast cancer, but the prognosis of the breastconserving surgery is worse than that of the modified radical mastectomy. Therefore, young breast cancer patients have to make their choice carefully.