Abstract: Objective To investigate the relationship between serum sodium levels and the severity of patients with liver cirrhosis. Methods The proportions of patients with serum sodium less than 135 mmol/L (hyponatremia) were compared between compensated and decompensated cirrhosis, and the proportions of hyponatremia patients were compared between patients with 1 and 2 (or more) complications in decompensated cirrhosis too. The data were analyzed by chi square test. Results In 580 cases of liver cirrhosis, 256 cases were in compensated stage and 324 cases were in decompensated stage. The proportions of patients with hyponatremia were 2.34% and 16.36% (χ2 = 30.74，P = 0.000) in patients with compensated and decompensated cirrhosis respectively, which had significant difference. In 324 patients with decompensated cirrhosis, the proportions of patients with hyponatremia and another 1 and 2（or more） complications were 14.09% and 42.31% respectively, and the two groups were significantly different (χ2 = 13.91，P = 0.000) . Conclusions There are more hyponatremia in patients with decompensated cirrhosis compared with compensated cirrhosis or with more complications in decompensated cirrhosis. Hyponatremia is closely related to the severity of liver cirrhosis, and the influence of hyponatremia in the severity of liver cirrhosis patients should be fully  onsidered.