Objective The purpose of this study was to explore the correlation between peripheral blood eosinophil (EOS) count and smoking history, some inflammatory indicators, lung function, efficacy of ICS, risk of respiratory failure and chronic pulmonary heart disease, risk of acute exacerbation within 1 year, readmission rate and mortality in patients with acute exacerbation of COPD. Methods Retrospective analysis of the baseline clinical data of 816 patients with acute exacerbation of chronic obstructive pulmonary disease in the Department of Respiratory and Critical Care Medicine of the First Affiliated Hospital of Shihezi University from January 1,2019 to December 31,2021. The patients were divided into EOS ≥ 200 cells / μL (High Eosinophi, HE) group and EOS<200 cells / μL (low Eosinophi, LE) group according to whether the peripheral blood EOS was greater than 200 cells / μL at admission. Peripheral venous blood data (including blood eosinophil count, white blood cell count, lymphocyte percentage, neutrophil percentage), blood gas analysis value, lung function index and medication regimen of all patients were collected, and the efficacy of ICS was recorded. The patients were followed up for 1 year to observe the acute exacerbation and readmission rate, and the mortality rate was followed up for 1 year and 2 years. Results Neutrophil count, lymphocyte count and peak expiratory flow (PEF) in HE group were positively correlated with EOS value (P<0.05), and smoking was more likely to increase EOS value. HE group was more sensitive to ICS. The risk of acute exacerbation in HEA group was higher than that in LE group. ICS could reduce the rate of acute exacerbation in HE group. EOS value in LE group was inversely proportional to FEV1 / FVC and MMEF values (P<0.05). The risk of chronic pulmonary heart disease in LE group was higher than that in HE group. The 2-year mortality rate in HE group was higher than that in LE group. Conclusions Peripheral blood EOS count is correlated with some inflammatory indicators, acute exacerbation risk, and lung function. ICS can improve the clinical symptoms and prognosis of patients with higher EOS count.