Breast nodules can be detected by ultrasound during lactation. The difference between breastfeeding breast and usual breast is lobular hyperplasia ductal dilatation. Breast nodules can be seen as inflammatory lesions, benign tumors or lesions, and malignant tumors, all of which can be detected. Inflammatory lesions are most often seen during lactation, due to sucking of the fetus, which may cause infections, resulting in inflammatory lesions of the breast tissue, which can manifest as nodules. Mammary hyperplasia or benign tumors can still be detected during breastfeeding. Mammary hyperplasia nodules may appear differently with changes in the menstrual cycle, and benign tumors are less variable and have clearer borders. Malignant nodules can also be detected more clearly during breastfeeding. Malignancy is characterized by indistinct borders and a harder texture, whether or not one is breastfeeding. Breast nodules can be detected regardless of whether or not they are breastfeeding, and patients with breast nodules are advised to go to the hospital in a timely manner to clarify the cause of the disease and then carry out targeted treatment.