Protective layer thickness control device

The invention provides a protective layer thickness control device, and relates to the technical field of building construction. The control device comprises two limiting pieces and a plurality of sets of adjusting assemblies, wherein the two limiting pieces extend in the length direction of a prefabricated beam, one of the two limiting pieces is used for being in contact with the outer edge of one of vertical main ribs in the prefabricated beam, and the other one of the two limiting pieces is used for being in contact with the outer edge of the other set of vertical main ribs; the plurality of sets of adjusting assemblies are arranged at intervals along the length direction of the prefabricated beam, each set of adjusting assemblies is connected with two limiting pieces, and a preset distance is formed between the two limiting pieces; and the two limiting pieces are used for abutting against the outer sides of the two sets of vertical main ribs respectively, so that the spacing between the two sets of vertic