Objective To investigate the levels of TNF-α in serum and gastric mucosa before and after military stress and their significances. Methods The level of serum TNF-α in 60 soldiers was studied by enzyme-linked immunosorbent assay. The expression of TNF-α in gastric mucosa from the 60 soldiers was detected by immunochemical staining. Results The level of TNF-α in serum in the soldiers was (92.93±30.98)pg/ml after military maneuver, and was significantly higher than that of (38.05±15.49) pg/ml before military maneuver (P<0.01). TNF-α was found to be expressed in the lamina propria epithelioglandular cells and in the mesenchymal mononuclear cells in gastric mucosa of the soldiers before and after military maneuver. The expression of TNF-α was also significantly stronger after military maneuver compared with that before military maneuver (P<0.01). Conclusions TNF-α might be involved in the development of the pathological changes of gastric mucosa caused by military stress in the troops. It will be helpful to examine the level of TNF-α in the early stage of military stress for evaluating the possibility of the occurrence of gastric mucosa lesion and its severity.