Objective ·To explore clinical and pathological characteristics, prognosis and potential related factors of breast cancer patients with brain metastases. Methods ·Seventy-five female breast cancer patients with brain metastases admitted to Renji Hospital, Shanghai Jiao Tong University School of Medicine from January 2007 to December 2021 were selected. The clinical and pathological characteristics of the patients were collected through clinical electronic cases, and the overall survival after brain metastases (OSBM) of the patients was collected during the follow-up period. Receiver operating characteristic curve (ROC curve) was used to evaluate the predictive efficiency of different biochemical factors on OSBM. Kaplan-Meier survival curve was used to analyze the correlation between different clinical and pathological characteristics and patients' OSBM. Cox proportional hazards regression analysis was further performed on statistically significant factors to determine independent influencing factors. Results ·The OSBM of 75 patients was 11.0 (5.0, 24.0) months. The results of ROC curve showed that carbohydrate antigen 125 (CA125) had a good prediction effect on OSBM, and its best cut-off value was 22.3 U/mL. The results of Kaplan-Meier survival analysis showed that the patients whose first metastatic site was brain (P=0.046), whose extracranial disease status was progressed (P=0.042), whose brain metastasis involved one side of tentorium (P=0.013), whose CA125 level<22.3 U/mL (P=0.000), whose treatment methods incladed regional therapy (P=0.034) and whose modified Graded Prognostic Assessment (mGPA) score>1 (P=0.001), had longer OSBM. Cox proportional hazards regression analysis showed that brain metastasis involving both sides of tentorium or meningeal (P=0.029), and CA125 level≥22.3 U/mL (P=0.005) were the risk factors for OSBM, and mGPA score>1 (P=0.033) was the protective factor. Conclusion ·The position of brain metastases in breast cancer, the level of CA125 and the mGPA score are important factors affecting the prognosis of patients.