P16 protein is a cell cycle regulator involved in the genesis of many types of tumors. In order to study the significance and expression of P16 protein in liver tissue of viral hepatitis, 48 patients with viral hepatitis and 7 cases with hepatocarcinoma were investigated by immunohistochemistry. The results showed that the positive rate of P16 protein expressed in the liver tissues of mild (85.0%) and moderate (91.66%) chronic viral hepatitis were significantly higher than that in liver cirrhosis and hepatocarcinoma (P < 0.01, 0.001), this suggest that the expression of P16 plays an important role in the carcinogenesis.