Objective To analyze the clinical value of multi-slice spiral CT pulmonary angiography in the diagnosis and treatment of emergency pulmonary embolism. Methods The medical records and imaging data of 72 patients with pulmonary embolismwho underwent multi-slice spiral CT or MRI examination were collected. Patients undergoing spiral CT pulmonary angiography were included in CT group (n=48) while patients undergoing routine MRI angiography were included in MRI group (n=24). The imaging data of two groups were analyzed. The image display and diagnosis were compared, and the characteristics of multi-slice spiral CT pulmonary angiography were analyzed. Results Compared with the MRI group, the diagnostic accuracy (91.67%), sensitivity (70.83%) and image quality score in CT group were significantly higher, and the scanning time was shorter (P<0.05). Multislice spiral CT diagnosis included diagnosis of acute and chronic thrombosis, and the common site of embolism was bilateral. Extent of lesions included distal left and right pulmonary arteries, pulmonary lobar arteries, and pulmonary segment belowarteries, etc. The direct signs included filling defects of pulmonary artery or branches while indirect signs included mosaic sign, limited lung markings or sparse, pulmonary hypertension or expansion, pleural or pericardial effusion, and effusion or infarction of some pulmonary segments. Conclusion Multislice spiral CT pulmonary angiography is accurate in the diagnosis of emergency pulmonary embolism, with high sensitivity and good image quality, and the imaging signs are obvious, which is of important value in clinical diagnosis and treatment of emergency pulmonary embolism.