Foam concrete building block

The utility model discloses a foam concrete building block which comprises a building block body, a first groove is formed in one end of the building block body, a first tenon matched with the first groove is fixed to the end, away from the first groove, of the building block body, and a plurality of second grooves are fixed to the side edge, perpendicular to the first groove, of the building block body. The building block body is perpendicular to the first groove, a plurality of second tenons matched with the second groove are fixed to the side edge, away from the second groove, of the building block body, a plurality of hollow cavities are fixed into the building block body, the building block body is sequentially provided with a first reinforcing layer, a buffer layer, a second reinforcing layer and a compression-resistant layer from inside to outside, and a plurality of semicircular protrusions are fixed into the buffer layer. A supporting plate matched with the semi-circular protrusion is fixed to the ou