Primary Hepatocellular Carcinoma (PHC) is one of the most common malignant tumors in the world. In men is the fifth most frequently diagnosed cancer worldwide but the second most frequent cause of cancer death. In women, it is the seventh most commonly diagnosed cancer and the sixth leading cause of cancer death. An estimated 748,300 new liver cancer cases and 695,900 cancer deaths occurred worldwide in 2008. Half of these cases and deaths were estimated to occur in China. Surgical resection and liver transplantation can be curative treatment options, but less than 20% of PHC patients are candidates for surgery. The prognosis of patients with unresectable PHC is poor; if left untreated, the median survival is less than 6 months. Since transarterial chemoembolization (TACE) was introduced as a palliative treatment in patients with unresectable HCC, it has become one of the most common forms of interventional therapy. However, the possibility of treatment-related complication may offset the survival benefit, especially by the worsening of liver functions.TACE increases several parameters of hepatic cytolysis and decreases the metabolic activity of the liver. Such a deterioration of liver function due to ischemia following TACE may result in liver failure, or even death. TACE also may have an adverse effect on the kidney. Radiographic contrast medium is used to obtain the hepatogram before TACE. It has been shown that the use of contrast medium increases the risk of renal failure, especially the low-osmolar contrast media. The aim of this trials was to compare the change of liver and renal function after TACE for HCC of iso-osmolar contrast media with that of low-osmolar contrast media.