Abstract: To study the alternation and the clinical significance of detection of plasma neuropeptide Y in patients with liver cirrhosis. Of the Patients with liver cirrosis (n=64) , males 40, females 20, aged 45±23 years, 57 had hepatitis B cirrhosis, 4 alcoholic cirrhosis, 2 hepatits C cirrhosis, 1 cardiovascular cirrhosis, with GI tract bleeding 20, ascites 36, hepatic encephacopathy 12 and hepatorenal syndrome 4. According to child's classification 28 cases were in group A, 23 in group B and 13 in group C. The levels of plasma neuropeptide Y in fasting state were measured by using RIA, and 40 healthy people (n=40; 26 males, 14 femals, aged 42±20 years) were tested as controls. Plasma concentrations of neuropeptide Y in group A (121.6±28.9 pg/ml) was lower than that in healthy controls (142.3±40.5 pg/ml) (P<0.05) , and group B (63.4±24.8 pg/l) , group C (45.6±21.7 pg/ml) were singnificantly lower than that in healthy controls and group A (P<0.01) . The levels of plasma neuropeptide Y was significantly lower in patients with liver cirrhosis, and was aggravated with the degree of injury of the liver function. It suggested that NPY may take part in the pathogenesis of the liver injury and was related with the classification of liver function.