[Objective] To obtain the high-yield κ-carrageenase by the recombinant strain BL21-HTa-cgkZ. [Methods] The optimal fermentation conditions of the recombinant strain BL21-HTa-cgkZ were determined by using single factor design and response surface analysis in the flask. [Results] The optimal medium compositions were composed of lactose 7 g/L, tryptone 10 g/L, yeast extract powder 5 g/L, NaCl 10 g/L and CaCl2 0.666 g/L. The optimal induction condition was adding IPTG 0.89 mmol/L after inoculation for 1.55 h and maintaining the fermentation at 23.03 °C for 24 h. The distribution of κ-carrageenase expressed by recombinant strain BL21-HTa-cgkZ was also affected by the additive such as lactose and triton X-100 in the medium. [Conclusion] The results provide the clues for the mass production of κ-carrageenase by the recombinant strain BL21-HTa-cgkZ.