Objective To study the application value of dual-source CT and digital subtraction angiography (DSA) in the diagnosis of acute pulmonary embolism (APE). Methods From May 2013 and December 2014, 50 patients with APE (study group) and 50 patients without APE (control group) in our hospital were enrolled in the study. All subjects underwent dual-source CT pulmonary angiography (CTPA) and DSA. The vascular parameters, pulmonary artery pressure, the maximum right ventricular/left ventricular transverse diameter ratio (RVd/LVd) and maximum area ratio (RVa/LVa) were compared between the two groups. The sensitivity, specificity and accuracy of dualsource CT and DSA in the diagnosis of APE were analyzed, and the imaging findings were evaluated. Results The pulmonary artery pressure [(49.92±1.68) mmHg], RVd/LVd (1.24±0.31) and RVa/LVa (1.20±0.39) of the study group were higher than those of the control group (P<0.05). There was no significant difference in the diameter of ascending aorta between the two groups (P>0.05). The diameters of main pulmonary artery [(31.04±1.58) mm], left pulmonary artery [(22.57±1.84) mm], right pulmonary artery [(25.29±1.64) mm] and right lower pulmonary artery [(14.29±1.07) mm] of the study group were higher than those of the control group (P<0.05). There were no significant differences in the sensitivity, specificity and accuracy between dual-source CT (86.67%, 100.00%, 88.00%) and DSA (91.11%, 100.00%, 92.00%) in the diagnosis of APE (P>0.05). Conclusion Both of dual-source CT and DSA have high application value in the diagnosis of APE. CTPA of dual-source CT can well show the anatomical information of lungs, while DSA can predict high pulmonary arterial pressure and pulmonary function, providing effective basis for the diagnosis of APE.