Acute mastitis during lactation is the most common disease in lactating women, occurring mostly within the first month after delivery, and is also a high incidence period in the seventh month after delivery, causing great physical and psychological pain to lactating women. Some of these patients progress to the abscess stage and are often faced with incision and drainage. Incisional drainage is relatively unobstructed and the inflammation subsides quickly, but the incision is large, with the possibility of poor incision healing and infection, milk fistula, and changes in the appearance of the breast scar, adding new worries and pain. Ultrasound-guided puncture and irrigation drainage can solve the problem and reduce the patient’s pain, while avoiding incision of the breast, reducing scarring and maintaining the beauty of the breast appearance. However, multiple punctures and drains may be required. The presentation of the swelling stage: redness, swelling and pain in the breast, localized lump with fluctuating sensation, significant pressure pain, with or without fever, and heterogeneous liquid dark areas on ultrasound. A 50 ml syringe needle was used to puncture into the pus cavity under ultrasound guidance, and the pus was extracted for bacterial culture and drug sensitivity testing. After the pus was extracted, the needle was not removed, and another syringe was used to repeatedly flush the pus cavity with saline until the extracted fluid was clarified, and the liquid dark area under B ultrasound basically disappeared. Ultrasound review is performed every other day, and if a dark area of fluid is still detected, the puncture flushing is repeated. For large single-chamber abscesses with 2-3 adjacent chambers, a drainage tube (connected to a drainage bag) is placed at the bottom of the abscess cavity and a flushing tube is placed at the top of the abscess cavity. Both the flushing tube and the drainage tube are fixed to the skin of the incision with silk sutures and repeatedly flushed.