Objective: To study the predictive effect of serum angiopoietin-2 on the condition of patients with community-acquired pneumonia, aiming to provide a scientific basis for early clinical intervention. Methods: From January 2020 to December 2021, 145 patients (81 males and 64 females) who met the diagnostic criteria of CAP (Community Acquired Pneumonia) were selected. A total of 145 patients were scored and divided into three groups according to the Pneumonia Severity Index (PSI), 72 cases in the low-risk group, 46 cases in the moderate-risk group and 27 cases in the high-risk group. Meanwhile, 70 people who had physical examination in the First People's Hospital of Zhengzhou City were selected as the control group. The medical records were checked to collect basic data of patients such as age, sex, body mass index, smoking history, drinking history, etc. Venous blood was collected on the day of admission (the day of physical examination in the control group) to measure the level of CRP (C-reactive protein), PCT (procalcitonin), TNF-α (tumor necrosis factor-α), Ang-2 (serum angiopoietin-2), WBC (white blood count), NLR (neutrophil to lymphocyte ratio), and PLR (platelet to lymphocyte ratio). Results: There was no significant difference in age, male proportion, BMI, smoking and drinking history between the groups of CAP patients and the control group (P＞0.05). Compared with the control group, the levels of CRP, PCT, TNF-α, Ang-2, WBC, NLR in CAP patients were significantly improved, and the difference was statistically significant (P＜0.05). With the aggravation of the condition of CAP patients, levels of CRP, PCT, TNF-α, Ang-2, WBC, NLR and PLR were significantly increased (P＜0.05). Correlation analysis results showed that the level of Ang-2 in patients was positively correlated with CRP, PCT, TNF-α, WBC, NLR, and PLR level (r=0.458 , 0.368, 0.481, 0.512, 0.419, 0.268) (P＜0.05). ROC analysis results indicated that when the optimal cutoff value of Ang-2 was 5.051, the area under the ROC curve was 0.689, the standard error was 0.023, 95 % CI (0.125-2.004), with the sensitivity of 75.32 % in predicting death of CAP patients and the specificity of 70.38 %. Conclusion: The Ang-2 level of CAP patients was significantly higher than that of the healthy people, and could be increased with the aggravation of CAP. The Ang-2 level was positively correlated with CRP, PCT, TNF- α, WBC, NLR and PLR, suggesting that the level of Ang-2 could be used to predict the condition of patients with CAP effectively.