Acute respiratory distress syndrome (ARDS) is a common acute and critical disease in clinic. The clinical mortality is as high as 30%-40%. At present, there is no specific treatment. Erythropoietin (EPO), also known as erythrocyte- stimulating factor, erythropoietin, has a certain amount in normal human body, mainly synthesized by liver in infants and kidneys in adults, which can stimulate erythropoiesis. In recent years, more and more studies have shown that high-dose exogenous EPO administration has benefit effects on multi-organ protection. Therefore, we designed this prospective, double-blind, placebo-controlled trial for defecting EPO on the alveolar fluid clearance of ARDS. The study mainly answers the following questions: Does human erythropoietin accelerate the resolution of alveolar edema in ARDS? Is there any effect on hospital survival? The study will draw conclusions by comparing the control group with the experimental group.