Objective To investigate the effects of daytime continuous renal replacement therapy on the plasma level of inflammatory mediators in acute respiratory distress syndrome. Methods Daytime CRRT were used to treat the patients who suffered from ARDS and the TNF-α、IL-1β、6、8 plasma levels were measured by enzyme-linked immunoassay(ELISA)at 0,2,4,6,8,10,12 hour following CRRT and 12 hour post CRRT. Result TNF-α、IL-1β、6、8 plasma levels start to reduce at 2 hour and decreased to lowest levels at 6 hours following CRRT( P<0.001) and slightly elevated at 12 hours post CRRT but still lower than the levels before CRRT. Conclusion CRRT can effectively clearance these inflammatory mediators. The results suggest that the clearance of these mediators may mainly be due to absorption.