Objective:To investigate the value of antithrombin Ⅲ (AT-Ⅲ) in evaluating patients with decompensated hepatitis B liver cirrhosis and complicated with esophagogastric variceal bleeding (EVB).Methods:From January 1, 2018 to December 31, 2021, clinical data of 193 hospitalized patients with hepatitis B liver cirrhosis diagnosed in the Second Hospital of Shanxi Medical University were retrospectively analyzed, which included coagulation indicator (AT-Ⅲ), liver function indicators (total bilirubin, etc.), abdominal ultrasound results (portal vein diameter, portal vein blood flow velocity), and the occurrence of esophagogastric varices. According to the presence or absence of main complications, 193 patients with hepatitis B liver cirrhosis were divided into compensated group (60 cases) and decompensated group (133 cases). According to the presence or absence of EVB, 133 patients of decompensated group were divided into non-bleeding subgroup (96 cases) and bleeding subgroup (37 cases). The above indicators were compared among compensated group, decompensated group and their subgroups. The independent related factors of decompensated hepatitis B liver cirrhosis and EVB were analyzed. The level of AT-Ⅲ of each group were compared, and the relationship between AT-Ⅲ and Child-Pugh score was analyzed. The diagnostic capability of AT-Ⅲ in decompensated hepatitis B liver cirrhosis and complicated with EVB were analyzed. Mann-Whitney U test, independent sample t test, chi-square test, multiple logistic regression analysis, Pearson correlation analysis and receiver operating characteristic curve (ROC) analysis were used for statistical analysis. Results:The total bilirubin level of the decompensated group was higher than that of the compensated group, the portal vein diameter was larger than that of the compensated group, and the portal vein blood flow velocity was lower than that of the compensated group (31.50 μmol/L (21.90 μmol/L, 48.80 μmol/L) vs. 19.40 μmol/L (15.00 μmol/L, 25.50 μmol/L); (14.31±3.53) mm vs. (12.57±3.83) mm; (13.39±3.49) cm/s vs. (15.08±4.28) cm/s), and the differences were statistically significant ( Z=-5.76, t=-2.78 and 2.40; P<0.001, =0.006 and 0.018). The incidence of esophagogastric varices of the compensated group and the decompensated group was compared (40.0%, 24/60 vs. 87.2%, 116/133), and the difference was statistically significant ( χ2=64.06, P<0.001). The diameter of portal vein of the bleeding subgroup was larger than that of the non-bleeding subgroup, and the portal vein blood flow velocity was lower than that of the non-bleeding subgroup ((15.54±4.23) mm vs. (13.87±3.16) mm; (12.05±3.12) cm/s vs. (13.85±3.51) cm/s), and the differences were statistically significant ( t=-2.15 and 2.23, P=0.034 and 0.028). The AT-Ⅲ levels gradually decreased in the non-bleeding subgroup and bleeding subgroup of the compensated group and decompensated group, which were (79.52±16.02)%, (63.91±19.96)% and (35.92±13.69)%, respectively, the difference was statistically significant ( F=5.71, P=0.018). The AT-Ⅲ level of the compensated group was higher than that of the non-bleeding subgroup and the bleeding subgroup of the decompensated group, and the AT-Ⅲ level of the non-bleeding subgroup of the decompensated group was higher than that of the bleeding subgroup, and the differences were statistically significant ( t=5.11, 13.74 and 7.84, all P<0.001). The results of multivariate logistic regression analysis showed that total bilirubin and AT-Ⅲ were independent related factors of decompensation of hepatitis B liver cirrhosis ( OR (95% confidence interval (95% CI) 1.060 (1.018 to 1.104) and 0.945 (0.922 to 0.970), P=0.005 and <0.001). AT-Ⅲ was an independent related factor of decompensation of hepatitis B liver cirrhosis and complicated with EVB ( OR(95% CI) 0.902 (0.856 to 0.950, P<0.001). AT-Ⅲ was negatively correlated with Child-Pugh score ( r=-0.559, P<0.001). ROC analysis showed that the cut-off values of AT-Ⅲ in the diagnosis of decompensated stage of hepatitis B liver cirrhosis and complicated with EVB were 62.5% and 61.5%, the sensitivity was 88.3% and 89.2%, the specificity was 70.7% and 61.5%, and the area under the curve (95% CI) was 0.815 (0.755 to 0.874, P<0.001) and 0.899 (0.828 to 0.971, P<0.001), respectively. Conclusion:AT-Ⅲ is an important indicator in evaluating the severity of disease progression in patients with hepatitis B liver cirrhosis, and it has a certain clinical value in evaluating the bleeding tendency of patients with decompensated hepatitis B liver cirrhosis and complicated with esophagogastric varices.