Objective To explore the application value of Dual-energy CT iodine image in differentiating benign and malignant pulmonary lesions. Methods All 39 cases with pulmonary nodules or tumors (benign 11 cases, malignant 28 cases) were confirmed by pathology. Chest CT with dual-energy mode plain scan and double-phase enhanced scans were performed. The double-phase enhanced images were sent to the Dual-energy software, select the application of the "Lung Nodules" to acquire the iodine-image. The iodine-image CT values of lesions arterial phase (AP), venous phase (VP) and arteriovenous period (AV) were obtained by measurement and calculation. The differences of iodineimage CT value between benign and malignant lesions was compared by independent sample t test. Results There were no statistically differences among iodine-image CT value in both arterial and venous phase between benign and malignant lesions(t=﹣0.61, P>0.05; t=1.50, P>0.05). However statistically significant differences of iodine-image CT value in arterial-venous phase were seen between benign and malignant lesions (t=2.97, P<0.05). Conculusion Dual energy scanning iodine image provides a new diagnostic method in differentiating benign and malignant lesions, and has good application value in clinical.