Objective: To analyze the value of CTPA in assessing the dissolve of embolus and the function of the right ventricle dynamically. Methods:Twenty-three cases of massive pulmonary embolism were analyzed retrospectively. The pulmonary artery obstruction index and the right ventricular function parameters were collected and analyzed on CTPA before thrombolytic therapy, 24 hours and 14 days after therapy, respectively. Results:The pulmonary artery obstruction index decreased gradually, and there was significant difference before therapy, 24 hours and 2 weeks after therapy. Twenty-four hours after therapy, the maximal short axes diameter and the maximal transverse area of right ventricle(RVd, RVs) decreased significantly, the maximal short axes diameter and the maximal transverse area of left ventricle(LVd, LVs) increased significantly, and the RVd/LVd, RVs/LVs decreased apparently. The pulmonary artery symbolic pressure before and 24 hours after therapy were apparently different. There was no significant difference between azygos vein, the super vena cava, the main pulmonary artery and vein reflux before and after therapy. Conclusion:CTPA can evaluate the pulmonary artery obstruction degree and right ventricular function dynamically.