This study aims to explore the mechanism of NSAID-related gastric ulcer treated by JIA WEI WU QI SAN. Clean-grade SD rats were randomly divided into four groups. Group A was assigned as the control group. Groups B, C and D were intragastrically administered with 2.5mg/kg of indomethacin solution QD after 48 hours. After 15 days of treatment, group B was administered with 0.9% sodium chloride, group C was given rabeprazole (2mg/kg), and group D was administered with JIA WEI WU QI SAN (2g/kg). Abdominal aorta sampling was performed, and gastric tissues were isolated on the 29th day. The protein expression of p-P38MAPK and COX-2 were detected by western blot, while the concentration of PGE2 and IL-1 were determined by ELISA. (1) The expression of IL-1ingroup B dramatically declined in group D (P<0.01). (2)The expression of PGE-2dramatically increased in group D(P<0.01). (3) The expression of COX-2 increased in group D (P<0.05). (4) The expression of p-P38MAPK decreased in group D (P<0.05). JIA WEI WU QI SAN has multiple functions, including the activation of the p-P38MAPK signaling pathway, which promote the activation of COX-2, induce the arachidonic acid to increase the level of PG, and decrease the concentration of IL-1, thereby inducing an inflammatory reaction, and promote gastric mucosa repair.