Abstract: After the rats were injected with ¹³¹I-HIPDM by vein, much was taken by the lung. 14 normal individuals, 17 cases of chronic obstructive pulmonary emphysema, 5 cases of asthma were studied. The results showed that the metabolism and development of ¹³¹I-HIPDM in the lung may reflect on condition of the pulmonary endothelial cells or receptors. The clearance curve of ¹³¹I-HIPDM was slow in the patients with chronic obstructive pulmonary mphysema, especially the patients of smokers. The analysis of the lung clearance of ¹³¹I-HIPDM forms a new index of lung dysfunction.