The utility model relates to a reinforced concrete floor slab protective layer thickness support is to the preparation of current split heads support of the same kind in reinforced concrete floor slab, awkward technical problem and design. This support includes steel bar support and reinforcing bar stabilizer blade, and four steel bar support are the groined type welding for two liang, and the welding is equipped with the reinforcing bar stabilizer blade that the symmetry set up in the both sides well head of symmetry, its main points are steel bar support's reinforcing bar is clean apart from be 800~1000mm, and groined type perimetric length be 250mm, reinforcing bar stabilizer blade clean the same with cover to reinforcement thickness value of setting of steel bar support apart from length, the adjacent reinforcing bar of groined type steel bar support horizontal and vertically only the distance should be 2500~3500mm. Prop through the support abutment at the groined type end angle of steel bar support and reinforcing bar stabilizer blade to quick weld forming, bottom plate, stay tube, flexible pipe, layer board, registration arm are drawn together to the support stationary ladle, and steel bar support passes through the layer board to be supported, and the reinforcing bar stabilizer blade inserts in the registration arm.