There are two main types of embolism that can occur in patients with long bone fractures, one is called fat embolism and the other is called venous thromboembolism. Both of these are dangerous diseases, serious diseases in orthopedics, and serious enough to lead to the death of the patient, so they must be taken seriously. The reason for fat embolism is that after a fracture, fat droplets from the bone marrow cavity enter the ruptured blood vessel, and if they flow backward to the lungs, heart, and brain, fat embolism of the heart, lungs, and brain will occur. Venous thrombosis of the lower limbs occurs because of prolonged bed rest after a long bone fracture, which tends to lead to poor appetite of the patient, vascular damage due to irritation of the fracture end, and venous stasis, which tends to lead to thrombosis of the blood vessels. If the thrombus backs up to the lungs, heart, brain, it will produce corresponding symptoms of embolism, serious cardiac embolism, can lead to cardiac arrest or pulmonary infarction, life-threatening. Therefore, when a long bone fracture occurs, care must be taken to avoid lifting, try to have early surgical treatment and early activity to prevent these two dangerous complications.