Abstract: Objective To explore the application of color Doppler ultrasound （CDU） and ultrasound elastography （UE） in the diagnosis of breast cancer and axillary lymph nodes. Methods Select 80 cases of breast cancer patients who were treated in Nanjing First Hospital from January 1, 2017 to December 31, 2019. The CDU and UE were used, and the area under the curve （AUC） of receiver operating characteristic （ROC） was used to evaluate the diagnostic value of the two methods for breast cancer axillary lymph node benign and malignant. Results Postoperative pathological examination showed that of 80 breast cancer patients, 48 were malignant nodules and 32 were benign nodules. CDU examination of the two groups of patients showed that the ratio of tumor length to diameter in the benign nodule group was significantly higher than that in the malignant nodule group （P<0.05）. Color Doppler flow imaging （CDFI） in the benign nodule group was characterized by no blood flow type, and the malignant nodule group was mainly portal type （P<0.05）. Ultrasound elastography showed that patients with benign nodules was divided into main scores from 1 to 2, and malignant nodules was divided into main scores from 3 to 4 （P<0.05）. The AUC values of CDU diagnosis, UE alone diagnosis and combined diagnosis of axillary lymph node properties were 0.703, 0.818 and 0.901, respectively. Conclusions Combined examination of CDU and UE could improve the accuracy of differentiating benign and malignant axillary lymph nodes of breast cancer, reduced the misdiagnosis rate, and had important reference value for clinical tumor diagnosis.