The theoretical prediction of the cross-sections in the determination of the structure materials used in the fission and fusion technology is very important in terms of reactor safety. Also, theoretical cross-sections are necessary to evaluate the performance of structure materials, especially, in the lack or absence of experimental data. Nickel base alloys are one of the wide ranges of structural materials used in fission and fusion reactors. Therefore, the excitation functions of the (n, 2n) reactions on the structure material nickel with neutrons producing via fusion reactions are investigated in this study. Thus, the excitation functions for 58,60 – 62,64 Ni(n, 2n) reactions are calculated using some pre-equilibrium models which are the hybrid, the geometry depended hybrid and the two-component excitation models. The calculations are performed in the ALICE/ASH and the Talys 1.8 codes. Also, the equilibrium and pre-equilibrium effects on these reactions are investigated in this study. The obtained cross-sections are discussed and compared with the experimental data and the theoretical predicted data.