Hyaluronic acid modified with sphingosine-1-phosphate, and a medicine comprising the hyaluronic acid as an active ingredient, wherein the medicine can alleviate hepatic disorder caused by hypoxia/reoxygenation by protecting the liver sinusoidal endothelial cells, and the medicine can prevent and/or treat liver failure due to liver transplantation, hepatectomy, or other surgeries associated with liver ischemia/reperfusion.