Objective：To study effects of modified low potassium dextran（LPD） solution combined with sodium nitroprusside on en－dothelin-1（ET-1） in plasma and lung homogenate during ischemia-reperfusion injury of dogs. Methods：A total of 12 healthy adult hybrid dogs were randomly divided into two groups with six dogs in each group. In group A，left lungs were flushed with 50-60 ml/kg of hepatic modified LPD solution at a pressure of less than 40 mmH2O. In group B，left lungs were flushed with hepatic modified LPD solution and sodium nitroprusside with other measures the same as group A. Changes of ET-1 content in plasma and lung homogenate at 0，2 h and 4 h after reperfusion were observed by ELISA. At the end of the experiment，the variation of lung wet/dry weight ratio was calculated. Results：ET-1 contents in plasma and lung homogenate were not significantly different（P >0.05） and wet/dry weight ratio in two groups had significant changes（P<0.05）. Conclusions：Modified LPD solution can reduce ET-1 expression level and wet/dry weight ratio and relieve ischemia-reperfusion injury，however，modified LPD solution combined with sodium nitroprusside has no effect on ET-1 expression level and wet/dry weight ratio.