Objective To evaluate the correlation between acute pulmonary embolism(PE) and right cardiac function by multi-slice Spiral CT pulmonary angiography (MSCTPA), and assess the severity of patients with acute pulmonary embolism. Methods A retrospective study including 107 cases MSCTPA data, of which 57 cases with PE, 50 cases without pulmonary embolism, from January 2012 to November 2013. Using CT postprocessing software measured thoracic aorta and main pulmonary artery inner diameter ratio (PA/AO), right ventricular correlation parameter, including right ventricle diameter to left ventricle diameter ratio (RVD/LVD) and right ventricle area to left ventricle area ratio (RVA/LVA) on axial four-chamber (4-CH) sections and the largest of maximum minor axis diameters on axial sections (RV/LV-LD). To compare the difference of CT related right heart parameter between the groups of central PE with death,central PE survivor, peripheral PE and the control group. Results There were significantly different between PE group and the control group with CT-related right ventricular parameters RVD/LVD,RV/LV-LD,RVA/LVA in PE group(P<0.05) (excepting PA/AO). Statistically significant differences were found in these measurements (RVD/LVD,RV/LV-LD,RVA/LVA)comparing patients with central PE with death and central PE survivors and those with peripheral PE and control group(P=0.000). There were significantly different between central PE survivor and peripheral PE with CTrelated right ventricular parameters RVD/LVD, RVA/LVA, but there were no statistically significant differences between peripheral PE patients and the control group in all RV parameters. Analyze the cor dextrum measuring index ROC curve of central PE with death group, RVA/LVA is the best indicator of predicting early death (AUC=0.873), with a sensitivity of 100%,specificity71.2%. Conclusion MSCTPA not only is able to accurately diagnose acute pulmonary embolism, but also is an objective evaluation of all relevant parameters of the right ventricle. Which plays an important role in assessing the severity degree of acute pulmonary embolism.