Cardiac surgery, especially cardiac surgery under cardiopulmonary bypass, is often accompanied by complex changes in circulation and blood system. Good perioperative fluid management is helpful to maintain the stability of hemodynamics, ensure good tissue perfusion, and protect the functions of important organs. Human serum albumin (HSA) is a special blood product. This article introduces the special effect of HSA in cardiac surgery, such as reducing inflammation, improving microcirculation, and regulating coagulation disorders. Meanwhile, the influence of HSA on the prognosis of patients undergoing cardiac surgery is reviewed. These findings will clarify the advantages of HAS and facilitate the rational application of HAS for fluid management during cardiac surgery.