Objective To evaluate the prediction of prognosis of patients undergoing the continuous renal replacement therapy (CRRT) after cardiac surgery by the multiple organ dysfunction score (MODS), simplified acute physiology score Ⅱ (SAPSⅡ), and vasoactive-inotropic score (VIS). Methods Data of patients undergoing CRRT after the cardiac surgery from November, 2010 to June, 2014 in the Surgical Intensive Care Unit of Shanghai Chest Hospital were collected. Patients were divided into the survival group and death group according to the result of treatment. The severity of disease of all patients was evaluated one day after surgery and one day before CRRT. The prediction of prognosis of patients by 3 scoring systems was evaluated by the area under the receiver operator characteristic curve (AUCROC). Results A total of 32 adult patients with acute kidney injury (AKI) who underwent CRRT after the cardiac surgery were enrolled. Among them, 9 patients survived and 23 patients died. The mortality rate was 71.9%. The scores of MODS, SAPSⅡ, and VIS of the death group one day after surgery and one day before CRRT were significantly higher than those of the survival group. The differences were statistically significant (P<0.05 or P<0.01). AUCROC of VIS one day after surgery and MODS, SAPSⅡ, and VIS one day before CRRT were 0.821, 0.816, 0.800, and 0.768 respectively. The differences of any two of them were not statistically significant (P>0.05). The survival rate of the group with high VIS 90 d after surgery was significantly lower than that of the group with low VIS. The incidences of low cardiac output syndrome (LCOS) and exploratory thoracotomy of the group with high VIS were higher than those of the group with low VIS. Conclusion VIS one day after surgery and MODS, SAPSⅡ, and VIS one day before CRRT can ideally predict the prognosis of patients undergoing CRRT after cardiac surgery. VIS one day after surgery is the best early index. High VIS is correlated with the poor prognosis.