Abstract: Objective To explore the value of breast mammography in evaluating the effect of neoadjuvant chemotherapy (NAC) on patients with breast cancer.Methods Breast mammography images from 21 patients with breast cancer before and after NAC were collected，and the main changes of Xray signs were analyzed.Results After NAC，all of the 21 cases showed smaller tumor size，4 cases showed reduced mass-density locally，20 cases showed changes in tumor shape，9 cases showed reduced range of calcification，and 9 cases showed smaller axilla lymph nodes with reduced density.Conclusions Mammography findings are deferent between before- and after-NAC on patients with breast cancer. Mammography can be used to assess the efficacy of NAC.

Key words: Breast cancer, Neoadjuvant chemotherapy (NAC), Mammography；Treatment effect