Objective:To observe the correlation between the frontal P-wave axis and the severity of chronic obstructive pulmonary disease (COPD) and the prognosis evaluation system.Methods:Patients with COPD>45 years old who were followed up in the outpatient department of Hunan Chest Hospital from January to July 2022 were continuously selected as subjects. At the same time, the healthy people who examined in the health management center of our hospital were in the control group. Both groups of subjects completed electrocardiogram and pulmonary function tests. The level of frontal P-wave axis and the results of pulmonary function examination were recorded, and the differences of frontal P-wave axis between the COPD group and the control group were compared, so as to clarify the value of frontal P-wave axis in the diagnosis, disease severity and prognosis evaluation of COPD.Results:The level of forced expiratory volume in the first second/forced vital capacity(FEV1/FVC )in the COPD group was significantly lower than that in the control group, while the level of P-wave axis was significantly higher than that in the control group (all P<0.05). The receiver operating characteristic (ROC) curve of P-wave axis showed that the AUC of P-wave axis in predicting COPD was 0.96 ( P<0.001), the best cut-off value was 63.80, the sensitivity was 0.89, and the specificity was 0.93. There were significant difference in P-wave axis level, the forced expiratory volume in one second to forced vital capacity ratio (FEV 1%pred), body mass index (BMI) and BMI, airflow obstruction, dyspnea, and exercise capacity (BODE) index between groups according to the degree of airflow limitation (all P<0.05). Correlation analysis showed that P-wave axis level was positively correlated with BODE index ( r=0.77, P<0.001), and negatively correlated with pulmonary function FEV 1%pred ( r=-0.76, P<0.001). Conclusions:There is a good correlation between the level of frontal P-wave axis and the severity of COPD and the prognosis evaluation system, which has clinical application value.