To further understand the effects of endothelin-1（ET-1）, endothelin receptor（ETR）and tumor necrosis factor α（TNFα）on the pathophysiologic process after burn and combined burn-blast injury, transcription and expression of ET-1, ETR and TNFα, their relationship and their relations with tissue injury were studied with in situ and dot blot hybridization. The results showed that transcription and expression of ET-1, ETR, and TNFα all increased significantly in the lung after injury, and NO in plasma also increased. Though endothelin receptor A（ETAR）mRNA increased significantly in the lung after injury, the amount of ETR was down-regulated. Changes of these parameters were more significant in rats with combined burn-blast injury and related to the pathophysiologic changes of the lung. It is suggested that ET-1 and ETAR may play a role in the pathophysiologic process of combined burn-blast lung injury.