Abstract: Objective: To explore the influencing factors of medical treatment delay in breast cancer patients based on the Andersen model. Methods: A total of 365 breast cancer inpatients were selected as the research subjects.Paper self-filled questionnaires were used to collect data on medical treatment delay,tendency characteristics,enabling resources and demand characteristics.Based on univariate analysis and logistic regression analysis,the influencing factors of medical treatment delay in breast cancer patients were explored. Results: The rate of medical treatment delay in this study was 32.1%.The results of univariate analysis and logistic regression showed that the per capita monthly household income level(OR=0.339,P<0.05),social support level(OR=0.799,P<0.01),breast cancer awareness level(OR=0.854,P<0.01) and disease perception ability(OR=0.681,P<0.01) were negatively correlated with the risk of medical treatment delay，and choosing alternative treatments was significantly associated with the medical treatment delay risk increasing in breast cancer patients(OR=9.775,P<0.05). Conclusions: The rate of medical treatment delay for breast cancer patients is relatively high,and affected by multi-dimensional factors.It is recommended that the government formulate multi-level and multi-dimensional intervention measures for medical treatment delay to promote the early diagnosis and treatment of breast cancer patients.