The utility model relates to a drainage system, and particularly relates to an integral bathroom with a drainage device of the same floor. According to the specific technical scheme, the integral bathroom with the drainage device of the same floor comprises a main drainage pipe, a bathroom waterproof base and drainage pipes connected with the main drainage pipe; the bathroom waterproof base is provided with a plurality of installation holes and a floor drain installation hole for the installation of a floor drain; each drainage pipe comprises at least two PVC (polyvinyl chloride) pipes and a flexible connecting pipe for connecting the PVC pipes; each PVC pipe is provided with a support which is used for fixing the PVC pipe on the ground and can be adjusted up and down; the installation end of the bathroom waterproof base is positioned at the floor drain installation hole and is provided with an installation opening by which the floor drain can be installed in the installation hole; a drainage cavity is arranged at the position of the installation opening and is internally provided with a pressing plate in fit with the floor drain in a manner of pushing against the floor drain; the pressing plate is provided with a drainage channel communicated with the drainage cavity. By adopting the technical scheme, the integral bathroom with the drainage device of the same floor, which is convenient to install, improves the installation efficiency, and has a good seal performance, is provided.