Abstract: Objective To investigate the correlation between ultrasonic features and Ki-67 of breast cancers.Methods The expression of Ki-67 in tumor tissue in 80 cases with breast cancers who were examined by ultrasonography in preoperation were detected by immunohistochemical technique.Results In 80 cases of breast cancers, the expression of Ki-67 were positively correlated to tumor size, with tiny calcifications, with rich bloodstream and lymphatic metastasis(P＜0.05);the pression of Ki-67 was not related to mass edge and posterior echo attenuation(P＞0.05).Conclusion The ultrasonographic characteristics of breast cancer show correlation with the expression of Ki-67.Both combination of diagnosis and treating early breast cancer have some clinical significance.