Objective: The aim of this study was to investigate risk factors for the severity of breast abscess during lactation .Methods: A cross-sectional study was conducted using data from the Questionnaire survey of breast abscess patients. According to whether the maximum abscess diameter > 5 cm, the patients were divided into 2 groups for univariate and multivariate regression analysis. Results: 1,805 valid questionnaires were included . Univariate and Binary logistic regression analysis demonstrated that low education (OR = 1.5, 95% CI: 1.1-2.0, P = 0.005), non-exclusive breastfeeding (OR = 0.7, 95% CI: 0.6-0.9, P = 0.004), fever > 37.5℃ (OR = 0.7, 95% CI: 0.6-0.9, P = 0.003), flat or inverted nipples (OR = 0.7, 95% CI: 0.6-0.9, P = 0.005), antibiotic used (OR = 0.7, 95% CI: 0.6-0.9, P = 0.006), and non-medical massage (OR = 0.3, 95% CI: 0.2-0.4, P < 0.001) were the effective independent influencing factors for the maximum breast abscess diameter > 5 cm. Conclusion: Low education , non-exclusive breastfeeding, fever >37.5℃, inverted or flat nipples, antibiotic used, and non-medical massage history have adverse effects on the enlargement of the abscess cavity with lactating breast abscesses patients.