To solve the problem of depth discontinuity of three-dimensional (3D) images having steep surface on imaging depth direction when using current multi-planar anti-aliasing technique, a depth anti-aliasing algorithm based on classified mapping is proposed. As the imaging of solid-state volumetric true-3D display is characteristic of three-dimensional surface, two-dimensional curves generating from interception of YOZ (or XOZ) planar and three-dimensional surface are analyzed. A method of voxel decomposition based on adjacent multi-layers mapping is introduced, which conforms with human stereoscopic vision, as well as a type judgment algorithm of voxel mapping. The off-axis viewing angles under the conditions of depth continuity are expanded to some extent by means of self-adapted classified mapping of raw voxels. A solid-state volumetric true-3D display system is developed, and 3D images are tested on the system. The result shows that most 3D images have completely smooth surfaces out to large off-axis viewing angles (about 45° ), and a good depth continuity can be obtained.