Abstract: Objective: To investigate the clinical value of dual energy CT lung perfusion imaging (DEPI) combined with CT pulmonary angiography (CTPA) in patients with highly suspected pulmonary embolism (PE). Methods: Fifty subjects suspected of pulmonary embolism underwent dual-energy CT pulmonary perfusion imaging. The CTPA, DEPI, and both of fusion image were acquired using the Lung Perfusion Blood Volume (PBV) software. Through DEPI, CTPA and both combined detection of three methods, χ² test were used for the detection of three methods on pulmonary lobe level, pulmonary segment level and sub-segment level respectively to compare the different test results and analyzed whether the statistically significant difference in the test results. Results: Analysis the χ² test results found that DEPI, CTPA and combined detection of pulmonary embolism results showed no significant difference (P ＞ 0. 05) in lung lobe level; In the pulmonary segment and sub-segment level, three methods were statistically significant (P ＜ 0. 05) , especially the joint detection can improve the detection rate of isolated sub-segmental with pulmonary embolism in the sub-segment level. Conclusion: Combined DEPI and CTPA, can not only improve the sensitivity of pulmonary embolism but also keep the higher specificity. It also plays an important role in early and accurate diagnosis to help clinical treatment and estimate prognosis for pulmonary embolism.