Objective To explore the diagnostic value of non-contrast chest CT in acute pulmonary thromboembolism(APTE).Methods A total of 187 patients with suspected APTE who underwent non-contrast chest CT and computed tomography pulmonary angiography(CTPA)within 2 h were included.Among 187 patients,there were 89 patients with APTE(APTE group)and 98 patients without APTE(control group).The clinical characteristics and chest CT features between the APTE group and the control group were compared.The sensitivity and specificity of non-contrast chest CT findings in the diagnosis of central APTE and peripheral APTE were analyzed.Results Chest CT showed pulmonary artery hyperdensity sign in 35 cases in the APTE group and none in the control group,with the difference was statistically significant(χ2=47.414,P<0.001);Subpleural shadow appeared in 33 cases in the APTE group and 11 cases in the control group,with the difference was statistically significant(χ2=17.327,P<0.001).The sensitivity and specificity of pulmonary artery hyperdensity sign in the diagnosis of central APTE and peripheral APTE were 72.92%,100%and 0%,100%,respectively.The sensitivity and specificity of sub-pleural shadow in the diagnosis of central APTE and peripheral APTE were 39.58%,88.78%and 34.15%,88.78%,respectively.The difference was not statistically significant in pleural effusion,pulmonary artery diameter,or pulmonary artery diameter to aorta diameter ratio between the two groups.Conclusion The pulmonary artery hyperdensity sign on non-contrast chest CT is a useful sign of APTE,which can avoid CTPA examination.