Objective To analyze the effect of ulinastatin on inflammatory factors and lung function in exhaled breath condensate (EBC) of liver transplantation patients. Methods From April 2016 to April 2017, 50 cases of orthotopic liver transplantation (OLT) patients in Beijing Chaoyang Hospital were divided into two groups (25 cases in each group) using random number table method: ulinastatin group (group U) and saline control group (group N). Ulinastatin 10 kU/kg was diluted into 100 ml normal saline and continuous intravenous infusion was started before skin incision in group U, while equal volume normal saline was used in group N. The blood samples of radial artery and pulmonary artery were collected for blood gas analysis at 10 min before medication (T1), 10 min before hepatic blood flow occlusion (T2), 30 min after blocking hepatic blood flow (T3), 30 min after opening hepatic blood flow (T4) and 10 min before the end of operation (T5). EBC was collected at 20 min before treatment (ET1), 20 min before blocking hepatic blood flow (ET2), 20 min after blocking hepatic blood flow (ET3), 20 min after opening hepatic blood flow (ET4) and 20 min before the end of operation (ET5), the length of EBC collection was 20 min. The levels of tumor necrosis factor‑α (TNF‑α), interleukin (IL)‑8, IL‑10 and neutrophil elastase (NE) in EBC and serum at the above time points were detected, and the peak airway pressure (Ppeak), pulmonary dynamic compliance (Cdyn), arterial partial pressure (PaO2), alveolar‑arterial oxygen difference [P(A‑a)O2], oxygenation index (OI), respiratory index (RI) and other respiratory mechanics and pulmonary function indexes at T1‒T5 were recorded. Pulmonary complications within 3 days after operation were also recorded. Results There was no significant difference in Ppeak and Cdyn between the two groups (P>0.05). RI in group U was lower than that in group N at T4 (P<0.05), OI in group U was higher than that in group N at T4 (P<0.05). OI in group N was lower at T4 and T5 compared with T1 (P<0.05). Level of NE: There was no statistical significance in EBC and serum at each time point (P>0.05). Level of TNF‑α: Compared with ET1, the levels of TNF‑α at ET4 and ET5 in both groups were lower (P<0.05), the level of TNF‑α at ET5 in group U was lower than that in group N (P<0.05), compared with T1, the level of TNF‑α at T4 and T5 in group U was lower (P<0.05), the level of TNF‑α at T4 and T5 in group U was lower than that in group N (P<0.05). IL‑8 level: Compared with ET1, the levels of IL‑8 in EBC decreased at ET5 in group N and at ET3, ET4 and ET5 in group U (P<0.05), the levels of IL‑8 in EBC was lower in group U than that in group N at ET4 and ET5 (P<0.05), compared with T1, serum levels of IL‑8 in group N at T4 and T5 and in group U at T3, T4 and T5 were reduced (P<0.05), the serum levels of IL‑8 in group U at T4 and T5 was lower than that in group N (P<0.05). IL‑10 level: Compared with ET1, the levels of IL‑10 at ET3, ET4 and ET5 in group N were lower (P<0.05), the levels of IL‑10 at ET4 and ET5 in group U were higher (P<0.05), the levels of IL‑10 at ET4 and ET5 in group U were higher than those in group N (P<0.05). Compared with T1, the levels of IL‑10 at T3, T4 and T5 in group N were lower, the levels of IL‑10 at T4 and T5 in group U were higher (P<0.05). The levels of IL‑10 at T4 and T5 in group U were higher than those in group N (P<0.05). Within 3 days after operation, the incidence of pulmonary complications in group U (40%) was lower than that in group N (72%) (P<0.05). Conclusions The level of inflammatory cytokines in EBC can reflect the lung injury of patients. Ulinastatin can reduce the level of inflammatory factors in EBC, thus reducing the postoperative pulmonary complications.