Abstract: Objective: To explore the identification and application of ultrasonic elastic strain rate in mastitis and breast cancer patients. Methods: A total of 48 patients with breast cancer and 50 patients with mastitis who were admitted to hospital from June 2015 to October 2017 were selected. They were designated as mastitis group and breast cancer group, respectively. Both groups were diagnosed with Hitachi Totem Color Doppler Ultrasound after admission. During the examination, the patient was subjected to routine two-dimensional ultrasound examination. The patient was then subjected to elastic image examination, and the region of interest was selected. The system software was used to calculate the elastic strain rate ratio and plotted. The ROC curve was used to analyze the diagnostic and differential efficacy of ultrasonic elastic strain rate in mastitis and breast cancer patients. Results: Breast cancer and mastitis patients were diagnosed by pathological examination. The top two breast cancer types were:invasive ductal carcinoma, intraductal carcinoma, respectively:68.75% and 16.67%; mastitis ranked first The two were thickening of the catheter wall, with inflammatory cell infiltration and tube wall structure destruction with tuberculous granuloma, accounting for 36.0% and 34.0% respectively; both the mastitis group and the breast cancer group successfully completed the elastic image examination. The ultrasonic elastic strain rate of the group was higher than that of the mastitis group (P<0.05). The ROC curve results showed that the area under the ROC curve of the ultrasonic elastic strain rate was 0.935. The sensitivity, specificity and accuracy of the diagnosis of mastitis and breast cancer were:93.1%, 90.2% and 85.7%. Conclusion: The value of ultrasonic elastic strain rate for the identification of breast cancer and mastitis is ideal. It can obtain high diagnostic efficiency and provide a basis and reference for clinical treatment. It is worthy of popularization and application.