Building foundation pit engineering monitoring and protecting device

The utility model discloses a building foundation pit engineering monitoring and protecting device which comprises a base, a protecting frame fixedly installed at the top end of the base, a threaded rod connected to the output end of a first rotating motor, a sliding seat installed on the threaded rod in a threaded mode, a supporting plate fixed to one end of the sliding seat, and a fixing frame installed at the top end of the supporting plate. The output end of the second rotating motor is connected with a rotating rod, a first bevel gear is installed on the rotating rod, the first bevel gear is meshed with a second bevel gear, a first rotating shaft is installed on the second bevel gear, a first gear is fixed to the first rotating shaft, the first gear is meshed with a second gear, and a second rotating shaft is fixed to the second gear; a mounting plate is fixed to the top end of the second rotating shaft, a monitoring device body is mounted at the top end of the mounting plate, a supporting rod is mounted