Abstract: Objective To investigate the protective effects of high-dose ulinastatin on the vital organs in patients undergoing total arch replacement for type A aortic dissection. Methods Between September 2014 and March 2016, 66 patients with type A aortic dissection underwent total arch replacement at our center. Thirty-six of the patients received ulinastatin treatment at 300 000 U/8 h from admission to 3 days postoperatively and at 300 000 U/2 h during cardiopulmonary bypass surgery (UTI group), and the other 30 patients did not receive perioperative ulinastatin treatment (control group). The surgical data and blood biochemistry profiles on days 1, 3, and 5 postoperatively were compared between the two groups, and the postoperative ICU stay, re-operation for bleeding, ventilation for over 7 days, ultrafiltration for postoperative renal failure, tracheotomy, incidences of pulmonary and neurological complications and hospital death were also compared. Results The operating time, cardiopulmonary bypass time, ACP time, cardiac arrest time, the lowest rectal temperature and frequency of bilateral and unilateral antegrade selective cerebral perfusion were similar between the two groups (P>0.05). Compared with those in the control group, patients in UTI group had lower lactate, S-100 and neuron specific enolase levels on the first postoperative day and higher OI on the 1st, 3rd, and 5th postoperative days (P<0.05), but serum creatinine, blood urea nitrogen, total bilirubin, and alanine aminotransferase levels were comparable between the two groups (P>0.05). No significant differences were found in the frequency of re-operation for bleeding, ultrafiltration for renal failure, tracheotomy, neurological complications or hospital death after the operation between the two groups, but the patients in UTI group had a shorter ICU time, a less frequent long-term ventilation and a lower incidence of pulmonary infection (P<0.05). Conclusion High-dose ulinastatin offers protection on pulmonary function and lowers the specific brain injury markers in patients with type A aortic dissection after total arch replacement, but its protective effects on brain is uncertain.