Objective To investigate the diagnostic value of dual-energy CT pulmonary angiography (DE-CTPA) and dual-energy CT lung perfusion (DE-CTLP) in the assessment of pulmonary embolism comparing with pulmonary ventilation-perfusion scintigraphy. Methods Fifty patients suspected of PE (26 males, 24 females) underwent both DE-CTPA, DE-CTLP and pulmonary ventilation-perfusion scintigraphy. The results were compared and the correlation between the intravascular clots in DE-CTPA and the perfusion defects in DE-CTLP was analyzed. The sensitivity, specificity and accuracy of DE-CTLP for PE were assessed according to scintigraphic results which was considered as a "gold" standard. Result ( 1 ) Of 50 cases,920 segments in 46 cases were diagnostable, 4 cases were not included because of the poor image quality. lntravascular clots were found in 262 segments on DE-CTPA and perfusion defects in 266 segments were identified on DE-CTLP, while 268 segments were positive on scintigraphy. (2) The perfusion defects on DE-CTLP were correlated well with the clots on CTPA ( r = 0. 883, P < 0. 01 ). The Dual energy CT Lung perfusion imaging had a good consistence with scintigraphy (Kappa = 0. 940, P <0. 01 ). The sensitivity, specificity, positive and negative predictive value were 96. 2% (279/290), 98.0%(641/654), 95. 5% (279/292) and 98. 3% (641/652), respectively. (3)The radiation dose of DE-CTPA and CE-CTLP scan was(4. 37 ± 0. 47) mSv by using CareDose 4D technique. Conclusion DE-CTPA and CE-CTLP can provide pulmonary vascular morphology and parenchyma perfusion information which are useful and valuable for the diagnosis of PE.