The vergence-accommodation conflict in holographic stereograms is investigated. The visual distortion and fatigue caused by the conflict are analyzed. A method for generating full-parallax holographic stereograms without vergence-accommodation conflicts is proposed. Two-dimensional spatial and spectral samplings are carried out on both the hologram and the reconstructed planes. The depth cues of three-dimensional object points are introduced in the iterative process of calculating subholograms with different spectral components. The stereogram is a combination of holographic elements (hogels), and each hogel is formed by performing a weighted summation of subholograms, where parallax images and depth information are used to select the constituent subholograms. A proof-of-principle experiment is carried out in an optical system based on a spatial light modulator. The results show that the improved full-parallax holographic stereogram can control the focusing depths of points and guarantee consistency between the vergence and accommodation distances. The influence of the size of the hogels on holographic imaging quality is also investigated.