Abstract:〔Abstract〕 Objective To explore the application of ulinastatin in patients undergoing laparoscopic appendectomy. Methods100 patients who underwent appendectomy in Xingyang people's Hospital from March 2020 to March 2021 were selected as the research objects. They were randomly divided into observation group (Ulinastatin infusion) and control group (equal amount of 0.9% sodium chloride injection), with 50 cases in each group. The levels of inflammatory factors and stress indexes were compared between the two groups. Results The levels of serum cortisol (Cor), S100β, interleukin-8 (IL-8), interleukin-6 (IL-6), and C-reactive protein (CRP) at 1 and 3 days after operation in the two groups All were higher than before operation, the difference was statistically significant (P < 0.05); The levels of Cor, S100β, IL-8, IL-6, and CRP in the observation group were lower than those in the control group at the same time, and the difference was statistically significant (P < 0.05). The incidence of postoperative cognitive dysfunction (POCD) in the observation group was lower than that in the control group at 1 and 3 days after operation, and the difference was statistically significant (P < 0.05). Conclusion Ulinastatin can reduce inflammatory reaction and stress reaction in patients with laparoscopic appendectomy and inhibit S100 β To reduce the occurrence of POCD and other complications.