To explore the relationship between levels of lactate dehydrogenase (LDH), glucose (GLU) and serum ascites albumin gradient (SAAG) in serum and ascites and liver function grading and prognosis in patients with liver cirrhosis complicated with ascites. Methods The case data of 90 patients with cirrhotic ascites treated in our hospital from April 2017 to April 2020 were analyzed retrospectively. According to the Child-Pugh grading of liver cirrhosis, the patients were divided into group A (n=21, liver function grade A), group B (n=43, liver function grade B) and group C (n=26, liver function grade C). According to the prognosis, they were classified into survival group (n=76) and death group (n=14). The levels of LDH, GLU and SAAG in serum and ascites were compared among patients with different liver function grades and prognosis. Logistic regression was used to analyze the relationship between the levels of LDH, GLU, SAAG in serum and ascites and the grade of liver function, draw the survival curve and analyze the key factors affecting the prognosis of patients. Results The levels of serum and ascites LDH, GLU and SAAG in group C were higher than those in groups A and B, and the above levels in group B were higher than those in group A (P＜0.05). The levels of LDH, GLU and SAAG in serum and ascites were higher in death group than those in survival group (P＜0.05). ROC curve showed that the areas under the curves (AUC) of serum and ascites LDH, GLU and SAAG on liver function grading were 0.826, 0.823, 0.775, 0.830 and 0.922 respectively, and SAAG had the highest efficiency and the cut-off was 22.99 g/L and its sensitivity and specificity were 88.46% and 87.50%. Logistic regression analysis showed that SAAG level ＞22.99 g/L at admission was an independent risk factor for liver function grade C (P＜0.05). The 18 month survival rate of patients with high SAAG level (＞22.99 g/L) at admission was lower than that of patients with low SAAG level (≤22.99 g/L) (P＜0.05).Conclusion With the increase of LDH, Glu and SAAG levels in serum and ascites, the grade of liver function and the incidence of poor prognosis increased in patients with cirrhosis and ascites. SAAG level is an independent risk factor affecting the severity of liver function, which can be used as an important index to evaluate the prognosis of patients