A bacterium, having high chitinolytic activity, was isolated from sediment of Shantou Bay, named SWCH-6. According to its physiological and biochemical characteristics and 16S rDNA sequence, it was identified as Aeromonas hydrophlilla. The optimal chitinase fermentation conditions of strain SWCH-6 were conformed by single-factor experiments and orthogonal experiments, they were colloidal chitin 25.0 g/L, tryptone 10.0 g/L, seawater 1 L, pH 8.5, 32℃, 150 r/min for 72 h. In these conditions, its chitinase activity reached 0.39 U/mL. In addition, at 40℃and pH 5.0, its chitinase performed the highest catalytic activity and its chitinase activity could be enhanced by Cu2+, Fe3+ and surfactant toween-80; weakened by Zn2+, Mn2+ and surfactants SDS, detergent powder, and there were some differences from orther chitinases.