Objective To explore the effect of Ulinastatin on proinflammatory cytokines of patients undergoing operation of intracranial aneurysm embolization. Methods 40 patients undergoing operation of intracranial aneurysm embolization were randomly divided into 2 groups (n = 20): ulinastatin group (Group U), normal saline group (Group C). In group U, 6 000 IU/kg Ulinastatin was infused via vein before anesthesia induction, the group C received the injection of isovolume normal saline. Exsanguinated arterial blood at T1, T2, T3, T4 and T5 five time points were taken to measure TNF-α and IL-6 in serum. Results The contents of TNF-α and IL-6 in serum both increased at T3, T4 and T5 compared to that at T1 in both groups; both TNF-α and IL-6 significantly decreased in Group U compared to that in Group C at the same time point. Conclusion Ulinastatin may inhibit the release of inflammatory mediators and lighten cerebral ischemia-reperfusion injury in patients undergoing operation of intracranial aneurysm embolization.