〔Abstract〕 Objective To investigate the significance of serum high mobility group box protein B1 (HMGB1) in chronic obstructive pulmonary disease (COPD). Methods We selected 42 patients with acute exacerbation of COPD who were admitted to the department of respiratory medicine at Shenzhen second people’s hospital from January 1, 2019 to December 31, 2019. To analyze the difference and correlation of serum HMGB1, high-sensitivity C-reactive protein (hs-CRP) and lung function in patients with acute exacerbation of COPD and clinical remission of COPD; The receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of HMGB1 in the acute exacerbation of COPD. Results (1)The expression levels of serum HMGB1 and hs– CRP in the acute exacerbation stage of COPD were higher than those in the clinical remission stage， and the predicted value of FEV1% in the acute exacerbation stage was lower than that in the clinical remission stage (all P < 0.001); (2) HMGB1 was positively correlated with hs–CRP in the acute exacerbation of COPD (r = 0.778, P < 0.001)， HMGB1 was not correlated with the predicted value of FEV1% (r = -0.117, P = 0.460); (3) HMGB1 was positively correlated with hs–CRP in the clinical remission stage of COPD (r = 0.361, P = 0.019), HMGB1 was negatively correlated with FEV1% (r = -0.678, P < 0.001); （4） ROC curve analysis shows that HMGB1 has a good diagnostic value for acute exacerbations of COPD, with AUC of 0.761, sensitivity of 66.7 %, specifi city of 83.3 %, positive predictive value of 80 %, negative predicted value of 71.4%. Conclusion HMGB1 participates in the process of local airway infl ammation and systemic infl ammatory response, and is of great signifi cance for the prediction of acute exacerbations of COPD and the evaluation of the severity of the disease.