In order to optimize the expression of antifreeze protein SF-P, using Nisin as the inducer to induced the expression of recombinant Lactococcus lactis. The expression conditions of induction time, induced pH, induced temperature and inducer Nisin concentration were optimized. The optimal expression conditions were determined by SDS-PAGE and Western blot. Furthermore, the physiological characteristics of recombinant bacteria under freezing stress were investigated by comparing the growth status, the acid production of bacteria and the changes of sodium and potassium contents before and after freezing stress. The results showed that the optimal expression conditions were determined: pH of 7.0, Nisin concentration of 15 ng/mL, temperature of 25 ℃, and incubation time of 6 h. The recombinant strain SF-P2 could significantly improved the growth of Lactococcus lactis in the logarithmic phase and the stable growth lag following freezing, and had a significant improvement in fermentation of L. lactis following freezing. It also could effectively reduced the effect of freezing stress on the permeability of cell membrane, which played a role in protecting the physiological function of cells. The results showed that the recombinant strain SF-P2 had significant protective effects against cold stress.