Abstract: Biomass and carrageenase activity was used as the index, the effects of medium compositon and culture conditons on cell growth and enzyme production was investigated in shaking culture of P.carrageenovora ASY5.In order to increase the yield of carrageenase, the medium compositon and culture conditons were optimized for fermentation of Pseudoalteromonas carrageenovora ASY5.The optimal medium compostion was composed of carrageenan 5 g/L, tryptone 5 g/L, Na Cl 20 g/L, Ca Cl₂0.2 g/L, Na H₂PO₄·2H₂O 1.3 g/L, Na₂HPO₄·12H₂O 3.8 g/L, while the optimal culture conditions were determined as tempreture 18℃, initial p H6.5, inculation volume 2%, liquid volume 70 m L.Under the optimum fermentation process, the production capability of carrageenase by P.carrageenovora ASY5 was significantly improved.Compared to the basic technical contidtions, the biomass and enzyme activity at the optimum technique were increased by 80.4%and 52.2%, respectively.