Objective To investigate the expression of oncostatin M (OSM) in patients with sepsis and its role in early recognition of sepsis. Methods Thirty-four patients with sepsis admitted in Shanxi Bethune Hospital fromJune 3, 2021 to January 18, 2022 were selected as a sepsis group, 15 patients with community acquired pneumonia (CAP) as a case control group, and 16 adults who underwent physical examination in the same period were selected as a healthy control group. The patients in the sepsis group were followed up for 28 days and divided into a survival group and a death group. The serum OSM level and its correlation with clinical indexes (white blood cell, neutrophil, lymphocyte, sequential organ failure assessment score and acute physiology and chronic health evaluation Ⅱ) were analyzed, and the diagnostic value of OSM expression level in the early identification of sepsis was analyzed. Results Compared with the case control group and the healthy control group, the expression level of OSM in the sepsis group was significantly higher [(502.07±209.93)pg/mL vs. (368.22±65.95)pg/mL and (382.09±73.04)pg/mL, P<0.05]. However, the high expression of OSM had no significant correlation with white blood cell, neutrophil, lymphocyte or disease severity score (P>0.05), and there was no significant difference in serum OSM level between the sepsis survival group and the death group. Compared with white blood cell count, the high expression of OSM has certain diagnostic value in the early identification of sepsis. The area under the receiver operator characteristic curve of OSM in predicting sepsis was 0.794 (95% confidence interval 0.666 - 0.922, P<0.05), with the sensitivity of 79.4% and the specificity of 73.3%. Conclusion The expression of OSM in patients with sepsis is significantly increased, and the high expression of OSM has a certain diagnostic value in the early identification of sepsis.