Cast-in-place concrete floor slab thickness advanced control device and using method

The invention provides a cast-in-place concrete floor slab thickness advanced control device and a using method. The cast-in-place concrete floor slab thickness advanced control device comprises two parallel guide rails; the plurality of guide rail positioning assemblies are arranged at the bottom end of the guide rail so as to erect the guide rail on a beam rib; and the trowelling assembly is arranged between the two guide rails, and the trowelling assembly can roll along the guide rails to trowelling the concrete surface. When the advanced control device is used, the rail positioning assembly is inserted into concrete and erected on a beam rib, then the trowelling assembly is installed between the two guide rails so that the trowelling assembly can roll on the two guide rails to trowelling the surface of the concrete, and finally the advanced control device for the thickness of the cast-in-place concrete floor slab is dismantled. And the concrete surface at the dismantling position is trowelled manually. Ac