Objective To investigate the value of CT pulmonary angiography in the efficacy evaluation for acute pulmonary embo-lism (PE) in elderly patients. Methods Seventy-five acute PE patients admitted in our hospital from January 2009 to January 2016 were enrolled in this study. They were divided into the aged group (≥60 years old, n=41) and non-aged group (<60 years old, n=34). The patients from the former group were further divided into shock subgroup (n=21) and non-shock subgroup (n=20) according to the severity, and also assigned into thrombolysis subgroup (n=28), intervention subgroup (n=8) and surgery subgroup (n=5) according to the different treatments. The ratio of right/left ventricular maximum short axis diameter (RV/LV), the maximum diameters of main pulmonary artery (MPA), diameter of left pulmonary artery (LPA) and right pulmonary artery (RPA), and the maximum diameter of superior vena cava diameter (SVC), and CT pulmonary artery obstruction index (PAOI) were compared in the different groups before and after treatment. Results Before treatment, there were statistical significances in the parameters of MPA, LPA and RPA between the aged and non-aged groups, and in the values of RV/LV, MPA, LPA, RPA, SVC and PAOI between the shock and non-shock subgroups (P<0.05). After treatment, the PAOI was obviously decreased in the aged group (P<0.05), the PAOI and maximum diameter of MPA were reduced in the non-shock subgroup (P<0.05), and the values of RV/LV, MPA, LPA, RPA, SVC and PAOI were all remarkably lower in the non-aged group, and shock, thrombolysis, intervention and surgery subgroups (P<0.05). Pearson correlation analysis showed that brain natriuretic peptide and cardiac troponin Ⅰ were positively correlated with the ratio of RV/LV (P<0.05), and PAOI and RV/LV were negatively correlated with PaO₂ (P<0.05). ConclusionCT pulmonary angiography can make an accurate efficacy evaluation for acute PE in the elderly patients.