Abstract. Mammography (MG) is the only proven modality to reduce mortality of breast cancer and has been shown to reduce mortality from breast cancer, and ultrasonography (US) is a well-known adjunct to screening MG. BI-RADS classification is actually practical and correlation with histopathology on the palpable diagnostic cases. To explore the clinical value of combined detection of MG and US BI-RADS in the diagnosis of breast cancer, we examined 212 patients using MG and US (62 cases breast cancer and 150 cases benign leision). All selected cases were re-evaluated by BI-RADS MG alone, US alone, and combined MG and US. In the combined imaging assessment, BI-RADS 1-4a category was MG and US both no more than 4a, however, 4b-5a cacategory was considered as the score of MG and US both more than 4a. MG and US alone findings BI-RADS 1-4a level were 142 cases and 144 cases, respectively; 4b-5 level were 70 and 68, respectively; and for Combination, there were 166 cases 1-4a and 46 cases 4b-5 level. Our results demonstrated that the sensitivity of MG, US alone was 80.65% and 72.58 %, respectly; and specificity was 86.67 % and 84.67%, respectly. The sensitivity of MG and US in combination was 69.35%, however, the specificity was improved into 98.00%, and a positive predictive value was improved into 93.47%. The differences in specificity and positive predictive values between MG and combined imaging assessment, US and combined all were statistically significant (P<0.05). The specificity and positive predictive values of combined assessment was the highest, and the sensitivity and negative predictive values was the highest in the MG assessment. Combined imaging assessment is more effective in diagnosing breast lesions.