The invention relates to concrete back pouring region slurry stopping and building blocks and a construction method, wherein, the shape of each building block is cuboid or cylinder, the building blocks are solid building blocks and building blocks with holes, and the building blocks are provided with a plurality of protuberance strips and are made of rubber material; when the construction is carried out at the reserving position of the concrete back pouring region, the cross section at the end part is solidly built by the building blocks and a reinforcing steel bar gap at the bottom of the reserving position is filled by minitype cuboid building blocks or cylinder building blocks and is infilled by dry cement; the delamination is infilled by the cuboid building blocks and is caulked jointby the cylinder building blocks or the minitype cuboid building blocks, and then the gap is filled with the dry cement; the upper part and the lower part of every layer of the building blocks are both tiled with a layer of dry cement; when building to the position of the reinforcing steel bar at the upper part, the gap is filled with the cylinder building blocks or the minitype cuboid building blocks and is infilled by the dry cement; after all the cross sections are solidly built, the cross sections are solidly pressed and fixed. The invention is easy to become deformed, firm and durable as well as has the characteristic of being hard to affix other substances, and makes use of the strong hydroscopic property of the dry cement to play the role of stopping slurry.