Abstract: A study was carried out to test the effects of acute ammonia exposure on gene involved in inflammation of mudskipper Boleophthalmus pectinirostris. The mudskipper (15.14±0.05) g were randomly allocated to 2 groups (control group and exposure group) in triplicate for 96 h ammonia exposure. The 96 h lethal concentration 50 (LC₅₀) of ammonia in mudskipper is 8.99 mg/L total ammonia nitrogen (TAN; 0.11 mg/L non-ionic ammonia); Fish exposed to ammonia showed the mRNA expression of TNF increased significantly by 2-fold for 96 h; The mRNA expression of IL-1 increased significantly by 6-fold for 12 h; And the mRNA expression of IL-6 increased significantly by 1.5 fold for 12 h and 96 h; however, the mRNA expression of IL-8 decreased significantly for 24 h. This study indicated that the 96 h LC₅₀ of ammonia in mudskipper is 8.99 mg/L TAN; The mRNA expression of TNF, IL-1, IL-6, IL-8 increased significantly after fish exposed to ammonia for 48 h; The inflammation is considered as one of major causes of fish ammonia poisoning.