Passivated co-doped TiO₂-B models, with N+V and C+Cr co-doping, were constructed using multiple cell combination method and the calculation on the models were carried out by first-principles density functional theory. The dopant atoms N+V and C+Cr were in troduced into TiO₂-B as the candidate for high-performance Li-ion battery cathode material. By calculating the embedding site and the activation energy of diffusion path the most stable sites were determined in the co-doped model at low Li⁺concentration, the correspondent diffusion activation energies are 0.47, 0.42 eV, respectively, for N+V and C+Cr systems. The embedding voltage for N+V model at high-concentration of Li+ is 0.83⁰.97 V, is lower than 1.05⁰.97 V, is lower than 1.05¹.27 V for C+Cr model, suggesting N+V co-doped TiO₂-B is more suitable for Li-ion battery cathode material. By computing two co-doped materials' density of states (DOS), band gaps are 1.7, 1.4 eV, respectively, for N+V and C+Cr models, suggesting N and C mainly modify the structure of valence band, while V and Cr mainly modify the structure of conduction band.