Objective To explore the correlation between different ultrasound pulmonary artery systolic pressure (PASP) and high-resolution CT (HRCT) pulmonary artery width (PAD) in patients with chronic obstructive pulmonary disease (COPD). Methods A retrospective analysis was conducted on 473 patients with acute exacerbation of chronic obstructive pulmonary disease who were hospitalized in the First Hospital of Lanzhou University from January 2016 to December 2020. They were divided into four groups according to the degree of PASP elevation: PASP normal group: PASP≤36 mm Hg, 182 cases; mildly elevated group: PASP 37 to 50 mm Hg, 164 cases; moderately elevated group: PASP 51 to 70 mm Hg, 89 cases; severely elevated group: PASP>70 mm Hg, 38 cases. The PAD of chest HRCT and the width of the ascending aorta (AAD) on the same plane were measured, and the ratio of PAD to AAD (PAD/AAD) was calculated. The differences of PAD, AAD, PAD/AAD in different PASP groups of COPD were compared. The correlations between PASP, lung function, blood gas analysis and PAD, PAD/AAD were analyzed. Results With the decrease of FEV1%pred, FVC%pred, FEV1/FVC, PaO2 and SaO2 in the patients, PaCO2 increased, PASP gradually increased, PAD and PAD/AAD gradually increased. PAD and PAD/AAD were significantly different between the severely elevated PASP group and the other three groups, and there were significant differences between the moderately elevated group and the normal group, and between the moderately elevated group and the mildly elevated group. PASP and PaCO2 were positively correlated with PAD and PAD/AAD, and FEV1%pred, FVC%pred, FEV1/FVC, PaO2, SaO2 were negatively correlated with PAD and PAD/AAD. Multivariate logistic regression analysis showed that after adjusting for confounding factors, decreased FEV1%pred was an independent risk factor for PAD/AAD>1 in COPD patients. The receiver operating characteristic curve showed that the width of PAD and PAD/AAD had certain predictive value for PASP. Conclusions There is a significant positive correlation between different degrees of ultrasound PASP and PAD and PAD/AAD in patients with COPD. HRCT PAD has certain predictive value for PASP. The heavier the hypoxia and carbon dioxide retention, the worse the pulmonary ventilation function, the higher the pulmonary artery pressure, the greater the possibility of PAD and PAD/AAD.