Underground building anti-floating drainage system

The utility model provides an underground building anti-floating drainage system which comprises a basement composed of a bottom plate and side walls arranged on the periphery of the bottom plate in a surrounding mode, and backfill soil is arranged outside the bottom plate and the side walls. The anti-floating drainage system comprises an anchoring rod piece, one end of the anchoring rod piece is connected with the bottom surface of the bottom plate, and the other end of the anchoring rod piece is fixed in the backfill soil; the first drainage pipe network comprises a first water inlet end and a first water outlet end, the first water inlet end penetrates through the bottom plate to be communicated with the basement, and the water outlet end is communicated with a rainwater pipe of an urban pipe network system; the second drainage pipe network comprises a second water inlet end and a second water outlet end, the second water inlet end penetrates through the elevation drainage level arranged on the side wall t