The invention relates to an ecological interlocking slope protection vegetation brick and a preparation method thereof. The vegetation brick comprises a block body and a vegetation disk, the block body comprises a center portion, a mounting clamp block, a mounting clamp groove, the center portion is provided with a center hole, the vegetation disk is arranged in the center hole, the upper surface of the vegetation disk is lower than that of the center portion, the center portion is provided with a front side surface, a rear side surface, a left side surface and the right side surface in the vertical direction, the mounting clamp block is positioned on the front side surface and left side surface and extends to the direction far wary from the center portion, the mounting clamp groove is respectively recessed to the center direction of the center portion from the rear side surface and the right side surface of the center portion, thickness of the mounting clamp block and the depth of the mounting clamp groove are equal and smaller than the thickness of the center portion, and the mounting clamp block and the mounting clamp groove on the adjacent slope protection vegetation bricks are mutually meshed, so that all-directional interlocking is achieved. Bricks are paved without mortar concrete in interlocking and self-embedding manner, and the vegetation brick is simple and easy to operate, low in construction cost, high in construction efficiency and applicable to slope strengthening and ecological restoration.