Objective To explore risk factors of stroke-associated pneumonia (SAP) for elderly stroke patients in ICU, and analyze the predictive value of human leukocyte antigen-DR (HLA-DR) on monocytes for SAP. Methods During January 2015 to August 2016, 155 elderly patients with stroke were recruited. The level of monocyte HLA-DR expression was measured after admission and the incidence of SAP was recorded. The risk factors for SAP were analyzed by univariate and multivariate analysis. ROC curve was drawn to analyze prognostic value of HLA-DR. Results SAP occurred in 75 cases with occurrence rate of 48.4%, including 42 early-onset cases and 33 later-onset cases. Age (OR=11.532), Glasgow Coma Scale (OR=7.124), dysphagia (OR=8.846), mechanical ventilation (OR=15.184), atrial fibrillation (OR=7.869), smoking history (OR=11.784), diabetes (OR=7.185) were independent risk factors (all P<0.05). The expression rate of monocyte HLA-DR in the SAP patients was significantly lower than those in the patients without SAP (allP<0.05). Through the ROC curve analysis, the expression rate of HLA-DR that below 78.65% was the optimum cut-off value for prediction of SAP with the area under ROC curve of 0.922, the sensitivity of 80.0% and the specificity of 85.0%. The sensitivity to predict early-onset SAP was 90.5% (38/42), and to predict later-onset SAP was 66.7% (22/33). Conclusions Age, severe coma, dysphagia, mechanical ventilation, atrial fibrillation, smoking history and diabetes are risk factors for SAP in elderly stroke patients in ICU. The detection of monocyte HLA-DR has reference value for early prediction of SAP especially for early-onset SAP with higher sensitivity.