Abstract：Objective To explore the value of mammography in the diagnosis of breast diseases.  Methods From July 2021 to June 2022, ninety patients with breast disease were examined by ultrasound and mammography. Using pathological examination results as the gold standard, the detection rate, diagnostic accuracy, sensitivity and specificity of benign and malignant breast diseases were observed and compared. The inspection time and cost of the two methods were compared. Results Mammography showed higher detection rate, diagnostic accuracy, sensitivity and specificity of malignant lesions than ultrasound （χ2＝5.051, 21.745, 18.240, 4.286, all P＜0.05）. The time of mammography was shorter, but the examination cost was slightly higher than that of ultrasound examination, and the differences between the groups were statistically significant （t＝5.237, 74.672, all P＜0.05）. Conclusion In the diagnosis of breast diseases, mammography has a good application value, can accurately diagnose the nature of breast lesions, the type of the disease, and has a guiding role in the formulation of clinical treatment.