Abstract： Objective To detect the expression of triggering receptor expressed on myeloid cells-1 (TREM-1) in mice with acute necrotizing pancreatitis (ANP). Methods Male kunming mice (n = 50) were randomly divided to control group, ANP 24, 48, 72, 96 h group. ANP model was induced by intraperitoneally injection with 20% L-arginine at a dose of 4 mg/g each, 1 h apart. Mice in control group received intraperitoneally injections of same amount of normal saline. Serum amylase, creatinine, and ALT were examined and pathological evaluation of pancreatic tissues was performed. The expression of TREM-1 mRNA in peripheral blood leucocyte was determined by RT-PCR. The expression of TREM-1 protein in pancreatic tissue was detected by immunohistochemistry. Results Serum amylase, creatinine, and ALT in ANP 24 h were (9439 ± 1273)U/L, (84.8 ±75.9) μmol/L, ( 158.1 ± 122. 1 ) U/L, which were significantly higher than those in control group [ ( 2412 ± 297 ) U/L, (29.2 ± 19. 1 ) μmol/L, (41.4 ± 7.9 ) U/L) ]. The pathological scores of the pancreas in ANP group increased corresponding to time. The expressions of TREM-1 mRNA in ANP 24, 48,72, 96 h group were 15.55, 30.36, 15.77, 28.32, and the expressions of TREM-1 mRNA in ANP 48 h group was significantly higher than that in other groups ( P <0.01 ). The expressions of TREM-1 protein in the pancreas did not significantly change corresponding to time. Conclusions TREM-1 may be involved in the development of ANP by triggering other inflammatory factors.