After major operation, a series of complicated pathological and physiological changes will occur during the trauma and stress state. The protein synthesis is affected, which results in negative nitrogen balance. In addition, the release of inflammatory factors can damage the capillary endothelial cells and increase the permeability of micrangium, induce vascular colloidal albumin leakage to the extravascular tissue, decrease plasma albumin, make wound edema, eventually lead to postoperative hypoproteinemia. Except for albumin supplement, it should be aimed at the mechanism to control the stress response and reduce the leakage caused by the release of inflammatory factors to solve this problem radically in clinical work. The reports about the causes and treatment of hypoproteinemia after major surgery were reviewed to provide evidence for clinical treatment.