ObjectiveTo summarize the treatment measures and experience for one patient with acute pulmonary thromboembolism after modified radical mastectomy for breast cancer. MethodsThe discussion on MDT (multi-disciplinary team) of a breast cancer patient admitted to The First Hospital of Lanzhou University in March 2018 and the results of the discussion on acute pulmonary thromboembolism after operation were summarized. ResultsThis patient had many high risk factors for deep venous thrombosis of the lower extremities, such as obesity, advanced age, hypertension, malignant tumor, and surgical stress. The operative time was about 90 min and the blood loss was 30 mL, without nerve and vascular injuries. Acute pulmonary thromboembolism occurred suddenly on 10 days after operation, which led to heart failure. Eventually, the patient died of the peripheral circulatory insufficiency caused by respiratory failure and heart failure. ConclusionSurgeons should pay great attention to the perioperative management of the patients with many high-risk factors, who may occur acute pulmonary thromboembolism caused by deep venous thrombosis of lower limbs after radical mastectomy.