Bone contusion, i.e., trauma resulting in bone marrow damage producing congestion, edema or with a small amount of bleeding, has a change in the marrow composition without trabecular fracture. It cannot be detected by X-ray and CT because of the absence of fracture lines and bone deformation. Bone contusion is a common cause of pain after bone injury, and the main clinical manifestations are pain and pressure pain at the injury site, and even functional impairment. MRI is the most sensitive imaging method to detect bone marrow edema, which can show very early and mild bone marrow edema. Bone marrow edema generally has low signal in T1WI and high signal in T2WI and STIR images, and this signal change represents an increase in bone marrow extracellular fluid, and the degree and amount of extracellular fluid increase determines the strength and extent of abnormal signal due to edema; it can determine the existence and extent of bone contusion. It is an important guide for clinical treatment.