Objective To evaluate the predictive value of lactate dehydrogenase (LDH) to albumin (Alb) ratio (LAR) in the prognosis of severe pneumonia patients complicated with DIC. Methods A total of 312 patients with severe pneumonia hospitalized in the intensive care unit (ICU) of the Affiliated Changzhou No.2 People's Hospital with Nanjing Medical University from January 1, 2018 to March 1, 2023 were retrospectively collected. The clinical parameters, such as gender, age, underlying diseases, and lactate dehydrogenase, albumin etc. l of the first test on admission were collected. LAR, sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation Ⅱ(APACHEⅡ) within 24 hours were calculated. The firstly endpoint of the study was the incidence of disseminated intravascular coagulation (DIC), the secondary endpoint was the 30-day in-hospital mortality in severe pneumonia patients with DIC. Univariate and multivariate logistic regression were used to analyze the risk factors of severe pneumonia with DIC. The receiver operating characteristic curve (ROC curve) was drawn and the area under the ROC curve (AUC) was calculated to evaluate the predictive value of LAR for the incidence of DIC in patients with severe pneumonia. Results The level of LAR was higher in the severe pneumonia patients with DIC than the severe pneumonia patients without DIC [LAR median ratio 12.72 (8.72, 21.89) vs. 7.23 (5.63, 10.90), P<0.001]. Multiple logistic regression analysis showed that LAR [OR=1.071, 95%CI 1.038 - 1.106, P<0.001] was the independent risk factor of the incidence of DIC in the patients with severe pneumonia. ROC curve analysis showed that the AUC for LAR to predict the incidence of DIC was 0.723, 95%CI 0.650 - 0.796, P<0.001. When the LAR cut-off value was 8.08, the sensitivity was 79.7% and the specificity was 56.1%. Kaplan-Meier survival analysis curve showed that the patients in the above LAR cut-off value group had a significantly lower 30-day survival rate than those in the below LAR cut-off value group (P<0.001). In the subgroup analysis and numerical variable transformed analysis, LAR was still the risk factor of DIC. Conclusion The increased LAR is a high risk factor of the incidence of DIC and mortality in patients with severe pneumonia, which is useful for predicting prognosis of patients with severe pneumonia.