Abstract: Objective: Study the diagnosis value of CTPA combined with dual energy CT lung perfusion imaging(DEPI) in acute pulmonary embolism, and the sensitivity of the DEPI to diagnosis the acute pulmonary embolism. Methods: The experimental group with 20 New Zealand rabbits. Acute pulmonary embolism models of rabbits were established by injection of gelatin sponge through the ear vein. The control group 2 New Zealand rabbits injected saline via the same path. The CTPA scan and dual energy CT lung perfusion imaging were collected successively after 2 hours then kill all rabbits. Observe the rabbit lung tissue with the gross anatomy and microscope. With the pathology as the gold standard to evaluate the accuracy of CTPA combined with DEPI in the diagnosis of acute pulmonary embolism. Results: In the control group, the CTPA show pulmonary artery patency, no filling defect, DEPI images show a substantially uniform yellow and red color. Experimental group after embolization of CTPA show visible ground-glass attenuation, lung tissue lung texture sparse and Mosaic change in part of pulmonary artery corresponding lung tissue in New Zealand rabbits, and embolism regional perfusion images displayed in blue or black perfusion defects or uneven perfusion. Pathological examination revealed small pulmonary embolus occurs, CTPA found no vascular filling defect, and DEPI show is slightly uneven image with normal perfusion regional color. The sensitivity, specificity, positive predictive value and negative predictive value of CTPA and DEPI in the diagnosis of pulmonary embolism were 97.22%, 98.65%, 97.22%98.65%; 97.37%, 95.83%, 92.50%, 98.57%. Conclusion: DEPI with a high sensitivity for the detection of acute pulmonary embolism; CTPA combined with DEPI can improve the diagnostic rate of acute pulmonary embolism.