Abstract: Objective To study the clinical value of ultrasound guided core needle biopsy in diagnosis of breast cancer． Methods From January 2014 to January 2015 in our hospital, a total of 102 patients with breast masses had undergone ultrasound guided core needle biopsy, their pathological results were retrospectively analyzed and compared with post-operation pathological diagnosis． Results The results of core needle biopsy included breast cancer in 71 patients and benign lesions in 29 patients． Two patients were diagnosed as adenosis by needle biopsy, but they were confirmed to be breast intraductal carcinoma in situ by post-operative pathological examination． The specificity, sensibility and accuracy of the ultrasound guided core needle biopsy was 100%, 98．63%, 98．04%, respectively． Conclusion Ultrasound guided core needle biopsy is a safe, reliable and accurate early diagnostic method for breast masses before operation, which plays an important role in the choices of clinical treatment methods．