MRI, which is commonly referred to as magnetic resonance imaging, is very important for preoperative planning, and is mainly used to: 1) show the relationship between tumor and surrounding tissues; 2) clarify the size and extent of tumor invasion; 3) distinguish the tissue components in the lesion area; 4) determine the extent of intramedullary infiltration; 5) determine the relationship between tumor and surrounding important blood vessels and nerves. In addition, MRI is also used to observe and evaluate the efficacy of radiotherapy, chemotherapy and surgery for bone tumors, and is used for early and timely detection of comorbidities and whether there is recurrence and metastasis. MRI is more sensitive than X-ray plain film and CT in detecting bone tumors, especially in observing the extent of infiltration of lesions, the relationship between soft tissue masses and blood vessels, the extent of muscle edema, and the pathway of tumor expansion, but its display of bone cortex and calcification is poor.