Objective To investigate the validity of ultrasonic in Differentiating diffuse liver cancer and cirrhosis. Methods Study the Ultrasononic shows of 30 cases with liver cirrhosis and 12 cases with liver cancer,analyze the causes of missed diagnosis. Results The positive rate of liver cirrhosis was 100%(30/30), diffuse liver cancer was 83.3%(10/12),two cases with diffuse liver cancer was missed(2/12). Conclusion There are some differential in ultrasononic shows between diffuse liver cancer and cirrhosis,not only content with the diagnosis of liver cirrhosis,meanwhile,observe carefully the ultrasononic shows wether there are diffuse liver cancer or not.