Objective To explore the risk factors of perioperative insomnia in young patients with breast masses undergoing ambulatory Mammotome (MMT) minimally invasive surgery. Methods A total of 166 young female patients who were ≤40 years old, diagnosed with breast masses, undergoing ambulatory MMT between June and December 2016 in West China Hospital of Sichuan University were included in this study. Questionnaire survey and data about general condition, preoperative and postoperative Insomnia Severity Index (ISI), Hospital Anxiety and Depression Scale, and postoperative pain Visual Analogue Scale were collected in the enrolled population. Univariate analysis was used to screen the factors that might cause insomnia, and then multiple logistic regression analysis was performed to identify possible risk factors of insomnia. Results In the 166 young female patients, the mean age was (30.90±5.96) years, and the mean perioperative ISI score was 8.83±4.97. Slight insomnia was found in 39.7% (66/166) of the patients, moderate insomnia was found in 12.7% (21/166), and severe insomnia was found in 2.4% (4/166). The results of multiple logistic regression suggested that the number of breast masses [taking the number=1 as the reference, when the number=4, odds ratio (OR)=2.269, 95% confidence interval (CI) (1.917, 13.818), P=0.001; when the number>4,OR=9.359, 95%CI (4.507, 19.433), P<0.001] and the maximum diameter of breast masses [taking 1–10 mm as the reference, when the maximum diameter was 26–30 mm,OR=6.989, 95%CI (1.488, 32.785), P=0.014; when the maximum diameter >30 mm, OR=17.290, 95%CI (4.664, 64.071), P<0.001] were independent risk factors of the severity of perioperative insomnia in these young women. Conclusion It is recommended that psychological nursing and comprehensive admission education should be enhanced for young patients who have >3 breast masses or the diameter of the mass is >25 mm, aiming to improve the postoperative recovery of patients with high risk of insomnia.