Objective To investigate the role of Toll-like receptor 4 ( TLR4 ) and NOD-like receptor 3 (NLRP3)inflammasome in the liver injury of acute necrotizing pancreatitis (ANP) rat with obesity. Methods Twenty-four SD rats were randomly divided into normal group, ANP group, obesity group and obesity ANP group. The obesity rat model was established by continuously feeding high fat diet and the ANP model was induced by retrograde infusion of 5％ sodium taurocholate into the biliopancreatic duct. Rats were killed at 12 h after model establishment, and automatic biochemical immune analyzer were used for detecting serum AMY, LIP, ALT, AST, TG and TC. Pathological changes of pancreas and liver tissue samples were observed by miscroscopy and pathological score was recorded. The levels of MPO, CD68 , TLR4, NLRP3 and IL-1βin liver tissue were detected by immunofluorescence, and NF-κB and caspase-3 in liver tissue were detected by immunohistochemistry. Results The serum ALT and AST in obesity ANP group were significantly increased than those in ANP group (233. 00 ± 34. 44 U/L vs 102. 83 ± 8. 90 U/L,388. 00 ± 41. 60 U/L vs 282. 00 ± 21. 06 U/L);and liver pathologic score was also significantly higher than ANP group (6. 66 ± 1. 21 vs 3. 33 ± 1. 03);and CD68 + /TLR4 +, CD68 + /NLRP3 +, TLR4 + /NLRP3 +, MPO, NF-κB, IL-1β and caspase-3 level were all greatly higher in obesity ANP than those in ANP group, respectively (24. 16 ± 1. 47 vs 6. 66 ± 1. 21, 25. 00 ± 2. 60 vs 7. 00 ± 1. 41, 14. 16 ± 1. 47 vs 5. 50 ± 1. 04, 35. 33 ± 6. 88 vs 20. 83 ± 2. 48, 58. 80 ± 6. 75 vs 37. 63 ± 2. 96, 50. 00 ± 2. 36 vs 35. 00 ± 2. 82, 66. 00 ± 4. 04 vs 55. 00 ± 2. 60); and all the differences were statistically significant (all P<0. 05). Conclusions Liver injury was more severe in ANP rats with obesity, which may be related to the fact that obesity may enhance the activation of TLR4/NLRP3 signal pathway and result in the release of more inflammatory factors.