Foundation pit water stop supporting system in building foundation construction

The utility model discloses a foundation pit waterstop support system in building foundation construction, which comprises a foundation, a foundation pit is arranged in the middle of the foundation, slots are arranged on the surface of the foundation and positioned on two sides of the foundation pit, a positioning rod is inserted into the foundation through the slots, a fixing hole is arranged on the surface of one side of the positioning rod close to the foundation pit, and the fixing hole is communicated with the foundation pit. A bottom supporting plate is installed at the bottom of the foundation pit, the side supporting plates are installed on the two sides of the foundation pit, the bottom supporting plate and the side supporting plates are connected in a clamped mode through the clamping heads and the clamping grooves, the bottom supporting plate and the side supporting plates are stably installed, and positioning is accurate; the inserting grooves are formed in the surfaces of the two sides of the fou