We present a detailed theoretical study for the structural and electronic properties of the new synthesized hard material CrB4 under pressure ranging from 0 GPa to 100 GPa by first-principles calculations with density functional theory in this paper. The results at zero pressure are in good agreement with the available theoretical and experimental values. The pressure dependence of structure, bond length , the Mulliken overlap population of B–B bonds and Cr–B bond, density of states (DOS) and PDOS are successfully calculated and discussed. The calculated pressure dependence of structural property shows that both structural parameters and covalent bonds of CrB4 are insensitive to the pressure, the results strongly support that the high hardness of CrB4 compounds is derived from the feature of B–B bonds cage.