Abstract: Objective To investigate the value of early evaluation of neoadjuvant chemotherapy（NAC） response in breast cancer by using ultrasound quantitative indicators. Methods Sixty cases of breast cancer patients （64 lesions） in our hospital diagnosed by ultrasound guided biopsy were collected. All patients received 4-8 cycles of NAC and then treated with operation. According to the results of histopathology after surgery， the patients were divided into a significant response group（R group）and a nonsignificant response group （NR group）.All the patients underwent ultrasound twice，within one week before and three weeks after the first cycle of NAC，respectively. Four quantitative indexes were observed， including maximum diameter of lesions（D）， peak systole velocity（PSV）， resistance index（RI） and elastography strain ratio（ESR） by ultrasonic measurement. Four quantitative indexes before and after the first cycle of NAC were compared using paired sample t test. The receiver operating characteristic （ROC）curves were drawn and their sensitivity and specificity were analyzed. Results Among the 64 lesions，53 were in the R group and 11 in the NR group. In the R group， D， PSV， RI and ESR after the first cycle of NAC changed significantly compared with those before NAC （P＜0.001）. In the NR group， the four parameters had no significant change（P＞0.05）. According to the ROC curve fitting data， the values of lesion D decreased by 8.0％， PSV by 15.0％， RI by 3.6％ and ESR by 15.7％ in predicting the sensitivity and specificity for the early response of breast cancer to NAC were 64.2％， 63.4％， 83.2％， 88.7％ and 91.1％， 100％， 100％， 100％， respectively. Conclusion By monitoring the changes of D， PSV， RI and ESR， they may serve as reliable indicators for early evaluation of NAC on breast cancer.