Objective: To explore the relationship between serum sodium level and complications & clinical prognosis of patients with decompensated hepatitis-B related cirrhosis patients with ascites. Methods: Retrospective analysis was conducted on 98 admitted cases with decompensated liver cirrhosis from May 2015 to October. 2016, and hyponatremia group and normal group were arranged according to serum sodium level. Through stratified analysis, liver and renal function, serum albumin, Child-pugh score, degree of liver fibrosis and complications on admission were compared between the two groups. Two weeks after treatment, efficacies for ascites were also compared, besides, prognosis of 2 groups were noted and compared after discharge. Results: Forty eight cases (41.8%) of 98 patients whose serum sodium levels <130 mmol/L. In the hyponatremia group, the levels of transaminase (ALT&AST), creatinine (Cr), total bilirubin (TBIL), prothrombin time (PT), Child-pugh score on admission were significantly higher than those in the normal group, serum albumin level was lower than that in the normal group, the differences were statistically significant (P<0.05). The hepatic encephalopathy, hepatorenal syndrome, gastrointestinal bleeding, spontaneous bacterial peritonitis rates in the hyponatremia group and the normal group were 24.4% vs. 7.0%, 19.5% vs.5.3%, 10.5% vs. 26.8% and 24.4% vs. 8.8% respectively, the differences were statistically significant (P<0.05). Fourteen days after admission, efficacies for ascites of the two groups were 73.2% vs. 89.5% (χ2=4.421, P=0.036); within 12-month follow-up, fatality rates of the two groups were 36.6% vs. 15.8% (χ2=5.577, P=0.018). Conclusion: Serum sodium level is closely related with decompensated liver cirrhosis status, hyponatremia patients with more serious condition, poor efficacy and prognosis.