Spinal cord injury (SCI) is the damage to the structure or function of the spinal cord caused by factors such as traffic accidents, falls from heights, and sports traumas. Clinically, the core symptoms include motor function impairment, sensory loss, and disorders of defecation and urination. Its pathological essence involves the cascade injury triggered by neuronal necrosis, axonal rupture, and the disruption of the blood-spinal cord barrier (BSCB). When the spinal cord is injured, it will lead to serious consequences such as sensory loss and difficulties in defecation and urination, which greatly affect the quality of life of patients. The collateral disease theory is a crucial component of the traditional Chinese medicine system. Its core lies in exploring the normal physiological operation and abnormal pathological manifestations of the collateral vessel system, as well as its correlations with various diseases. This article starts from the collateral disease theory and combines the BSCB mechanism to analyze the pathogenesis and treatment approaches of spinal cord injury.