The invention relates to a compression forming die and method for a grinding wheel block. The compression forming die comprises a die frame, the die frame is provided with an arc die cavity extending in the vertical direction and matched with the radian of a corresponding grinding layer, the compression forming die further comprises an upper arc compression head and a lower arc compression head assembled in the arc die cavity in a sliding and guiding mode during use, and the shapes of the sections of the upper arc compression head, the lower arc compression head and the arc die cavity in the direction perpendicular to the vertical direction are the same as the shape of the section of the grinding layer. By means of the compression forming die and method for the grinding wheel block, raw materials can be saved when the grinding wheel block with a special-shaped section is compressed and formed, and it can be ensured that the axial and radial density is uniform when the grinding wheel block with a large axial and radial thickness is compressed.