Objective To summarize the effect of mild hypothermia on post-cardiac surgery patients with multiple organ dysfunction system(MODS). Methods We retrospectively analyzed the clinical data of 90 patients with MODS after cardiac surgery under cardiopulmonary bypass(CPB) from May 2010 through June 2014 in our hospital. There were 57 males and 33 females at 61±6 years. The patients were divided into two groups including a NT group (without pre-hypothermia treatment,n=32) and a HT group(with pre-hypothermia treatment,n=58). Results Of the 90 patients, totally 18 patients died, 8 patients (13.8%) in the HT group, 10 patients (31.2%) in the NT group with a statistical difference (P<0.05). In the NT group, 12 patients (37.5%) were treated by intra-aortic balloon pump (IABP), and 9 patients (15.5%) in the HT group with a statistical difference between the two groups (P<0.05). The patients' heart rate (HR) decreased significantly after the application of hypothermia. The HR of difference between the two groups at 36 h was significant (P<0.05). The mean aortic pressure (MAP) in the HT group was lower than that of the NT group significantly at 0 h, because we used sedation and muscular relaxation agent. But the MAP in the HT group was significantly higher than that of the NT group after hypothermia 36 h (P<0.05). In the HT group, pressure of oxygen (PO2), mixed venous oxygen saturation (SvO2), and lactic acid (Lac) were improved significantly compared with those of the NT group significantly (P<0.05). There was no statistical difference in prothrombin time (PT) or activated partial thromboplastin time (APTT) between the two groups (P>0.05). But there was a statistical difference in platelet (PLT) between the two groups at 36 h (P<0.05). The aspartate aminotransferase (AST), alannine aminotransferase (ALT), creatinine (Cr) were improved significantly in the HT group (P<0.05). Conclusion Mild hypothermia can improve the organ function effectively. It can slow the MODS development speed and win the time of protection and further treatment for cells and organs. It is an effective and safety therapeutic technique for MODS after cardiac surgery.