The aim of this study was to determine the histogram patterns and the diagnostic efficacy of liver echohistogram in chronic diffuse liver diseases. Abdominal ultrasound and liver echo-histogram were prospectively and blindly performed on 21 healthy controls, 24 patients with chronic hepatitis, 26 patients with liver cirrhosis, and 22 patients with fatty liver disease. Maximum liver echo intensity and echogenicity were decreased in chronic hepatitis. Increased anterior maximum liver echo intensity and echogenicity, decreased posterior maximum liver echo intensity and echogenicity, and reduced posterior/anterior maximum liver echogenicity ratio were found in fatty liver disease. The diagnostic efficacy indexes of abdominal ultrasound were enhanced by some echo-histogram data: anterior maximum echo intensity of the liver less than 20.52 decibels for chronic hepatitis and posterior/anterior maximum liver echogenicity ratio less than 0.231 for fatty liver disease. In liver cirrhosis, echohistogram showed a high dispersion of values and not enhanced the abdominal ultrasound diagnostic efficacy. In fatty liver disease, a positive correlation was found between percentage of hepatocytes with fatty change and anterior maximum echo intensity of the liver (rs = 0.47, p < 0.05), as well as between percentage of hepatocytes with fatty change and anterior maximum echogenicity of the liver (rs = 0.68, p < 0.01). These findings indicate that the liver echo-histogram improves the diagnostic efficacy of abdominal ultrasound in chronic hepatitis and fatty liver disease. We suggest that combined abdominal ultrasound and liver echo-histogram should be performed in the investigation of chronic diffuse liver diseases.