Objective To investigate and analyze the value of multi-slice spiral CT pulmonary angiography in the diagnosis of pulmonary embolism. Methods A total of June 2012 and 2015 June in 85 cases of our hospital for examination of the patients with pulmonary embolism underwent multi-slice spiral CT pulmonary angiography in the diagnosis of 43 patients as the observation group, the MRI angiography in the diagnosis of 42 patients as control group, and the two groups of diagnosis, image quality, scanning time dose were observed and compared. Results Observation group diagnosis specificity (79.07%) and accuracy (93.02%), sensitivity (82.5%), image quality rating (4.80 ±1.00) points were higher than those of the control group specificity (52.38%) and accuracy (61.94%), sensitivity (54.76%), image quality rating (2.30±0.50) points; The scanning time(6.60±2.00)s in the observation group was lower than that in the control group (580.00±150.00)s, and the difference was statistically significant (P<0.05). Conclusion The image quality of multi-slice spiral CT pulmonary artery angiography is higher, it can be more accurate to judge the pulmonary embolism, and at the same time, the scan time is greatly reduced.