The gills and guts of live Ovalipes punctatus were screened for histamine-forming bacteria (HFB) by HBI medium and TLC methods. Furthermore, the histamine-forming ability was evaluated by HPLC method, and the bacteria was identified by 16 S rDNA morphology sequence analysis. The effects of temperature, initial pH value and NaCl contents on the growth characteristics and histamine production as well as the inhibitory effects of chitooligosaccharide (COS) on the histamine-forming bacteria. One strain HFB was isolated, identified and named as Enterobacter aerogenes OP-G2 based on morphology and 16S rDNA sequence analysis. This strain could produce (46.96±1.94) mg/L histamine in TSBH medium after incubation at 30 ℃ for 48 h. The growth and histamine formation of E. aerogenes OP2-56 in TSBH medium could be effectively controlled both by low-temperature (≤ 4 ℃) and high NaCl content (≥ 10%), and the inhibitory rate for the strain could be up to more than 92%. Meanwhile, the growth of the strain could be effectively inhibited (all above 30.58%) by COS concentration higher than 0.5 g/100 mL, and the antibacterial rate of 1.0 g/100 mL COS at pH 6.0 against E. aerogenes OP2-56 could be up to 47.57%.