Abstract: Objective To discuss technique of computerized tomography (CT) scan in diagnosis of breast cancer and to investigate image characteristics of breast cancer in CT scan. Methods CT scan and reinforcement scan documents from 23 cases of breast cancer were reviewed. The diagnosis of all these 23 cases were confirmed with pathology of excised mass. Results CT scan was able to show the anatomical structure of breast clearly and find tumor with higher sensitivity. CT scan and reinforcement scan were also able to measure the size of tumor and to find out any change near tumor. Conclusions CT scan and reinforcement scan are ideal techniques for breast cancer either in diagnosis and differential diagnosis or clinical TNM staging and treatment decision.