Abstract: Based on the density functional theory and crystal structure analysis by particle swarm optimization (CALYPSO) structure searching method, the geometric structure, electronic and spectral properties were studied systemically for CoB₂₀⁻ cluster. First, the lowest energy and low-lying structures of CoB₂₀⁻ clusters were obtained with the PBE0/6−311+G(d) level. Results indicated that CoB₂₀⁻ cluster is composed of a cobalt atom sandwiched by two B₁₀ monocyclic rings. Second, electronic properties were analyzed by calculating the natural population analysis, natural electron configuration, Mayer bond order and electron localization functions. Finally, its photoelectron spectroscopy, infrared spectra and Raman spectra were simulated and discussed. We hope that our researches could provide powerful guidelines for future theoretical and experimental synthesis of cobalt-doped boron based on nanomaterials.