Abstract：Objective：To explore the distribution laws of traditional Chinese medicine (TCM) constitutions in breast diseases， analyze the relevant risk factors for constitutions which are predisposed to breast diseases， and provide references for the prevention and treatment of breast diseases. Methods： There were 126 patients with breast diseases were selected；their TCM constitutions were identified，and their general information was collected. All patients were divided into the breast cancer group and the benign breast diseases group according to their disease types. The distribution of TCM constitutions in the two groups was counted. Results：The age group with the largest distribution in the breast cancer group was over 50 years old， and that in the benign breast diseases group was between 35 and 50 years old， the comparison between the two groups showed significance in the difference (P＜0.05). The proportion of overweight patients in the breast cancer group was 52.5%，and that in the benign breast diseases group was 32.3% ， the comparison of the body mass index (BMI) values between the two groups showed significance in the difference (P＜0.05). The menopausal rate in the breast cancer group was 78.7%，and the menopausal rate in the benign breast diseases group was 21.5% ， the comparison between the two groups showed significance in the difference (P＜0.05). The most common constitution types in the two groups were qi constraint constitution， yang deficiency constitution， qi deficiency constitution， and phlegm- damp constitution. Through binary logistic regression analysis， it was found that temperament was positively correlated with qi constraint constitution (P＜0.05)；there was a positive correlation between overweight and phlegm- damp constitution (P＜0.05). Conclusion： Compared to benign breast diseases， patients with malignant tumors are older and have a larger proportion of overweight， suggesting that overweight may increase the risk of developing malignant tumors for women with age， and attention should be paid to early screening for breast cancer. Overweight people are more likely to have a phlegmdamp constitution，and those with irritable temperament are more likely to have a qi constraint constitution. People who are predisposed to breast diseases should undergo early adjustment and intervention for biased constitution and reduce the occurrence of breast cancer.