Band structure calculations were performed on the dense Kondo antiferromagnetic CeCuSb2 and revealed that the essential contribution to the total density of state (DOS) around EF originates from Sb 5p-Ce 5d bands while the contribution of Ce 4f band is rather small. Polarization-dependence of CeCuSb2 valence band HAXPES spectra was successfully observed. The experimental HAXPES results were described fairly well by the band structure calculations where the photoionization dependent cross section was taken into account.