The invention discloses a foundation pit erect column pile and a dismantling device thereof, and relates to the field of house building foundation pit enclosures. The foundation pit erect column pilecomprises an upper erect column and a lower erect column, the upper erect column is vertically and slidably connected with the lower erect column, the top end of the lower erect column is lower erectcolumn is rotationally connected with a big gear wheel, and the bottom end of the upper erect column is fixedly connected with a lifting threaded rod; the big gear wheel is rotated, thereby making thelifting threaded rod rise, making the upper erect column rise, making the upper erect column separated from the lower erect column, and dismantling the upper erect column; the dismantling device comprises a fixing block, a dismantling frame and a drive motor; a patchhole is formed in the fixing block, the drive motor comprises an output shaft, and the output shaft of the drive motor is fixedly connected with a pinion; the dismantling frame is rotationally connected with a rotating block; the rotating block is fixed with a fixing sleeve, the drive motor drives the pinion to rotate, thereby dismantling the upper erect column; and the fixing block is moved, thereby transporting the upper erect column, and providing convenience for placing and transporting the upper erect column.