Objective To evaluate the diagnostic value of the mammography and to raise the level of preoperative diagnosis.Methods The mammography of 139 cases were analyzed and the result was compared with that of pathology.Results The sensitivity was 91.43%, the specificity was 95.65%, the positive predictive value was 95.52%, the negative predictive value was 91.67%; the positive likelihood ratio was 21.03, and the negative likelihood ratio was 0.09; the false positive value and the false negative value were 4.3% and 8.6% respectively.Conclusion The signs of the most malignancy of breast can be shown by mammography. And the technique has very high value of the determinative diagnosis to be applied further.