Objective To investigate the diagnostic value of strain ratio for differentiation breast benign and malignant solid lesions. Methods Two hundred and sixty-nine patients with 377 lesions (278 benign, 99 malignant) were included in the study. Ultrasonography found the lesions, then ultrasonic elastography got the strain images. By the strain ratio measure method equipped with the ultrasonic machine, strain ratio of the lesion was calculated. Compared with the pathologic diagnosis, the cut-off point of strain ratio was determined with receiver operating characteristic curve. Results There was significant difference between the strain ratio of benign and malignant lesions( P <0. 05). The cut off point of strain ratio was determined as 3. 08, Youden's index was 0. 88,sensitivity was 97. 38% ,and specificity was 91. 33%. Conclusions Strain ratio could be used to differentiate benign and malignant lesions in breast and would be a new diagnostic standard in future.