Objective To screen and optimize the cell culture medium for monoclonal antibody(McAb)against tetanus toxin. Methods A basic medium with optimal components was screened by evaluation of growth and metabolism parameters of engineered CHO-K1-G2 cell strain for McAb against tetanus toxin in various serum-free com. media. The additives significantly promoting cell protein expression were screened from 23 kinds of additives by Design of Experiments(DOE). The screened basic medium was used for expand culture, and the target protein was purified by affinity chromatog. and analyzed for properties. Results Number 2 medium was defined as the basic medium for further optimization. In the turn of effect, the six screened additives were hypoxanthine, taurine, ethanolamine, lecithin, ferric citrate and aspartic acid. The optimal fitting value of cell protein expression level was 238. 22 mg/L. The antibody titer obtained by expand culture was 500 IU/mg, while the affinity constant was 1. 33 x 10-9/M. Conclusion A"personalized culture medium"that can promote the growth of CHO-K1-G2 cell strain and antibody expression was established, which laid a foundation of the establishment of an economical and efficient antibody drug production process.