The utility model discloses a locating device of a drilling rod at the bottom of a foundation trench, which comprises a circle of fender posts (1) at the edge of the foundation trench, wherein a locating device used for limiting the drilling rod (2) is arranged at the bottom of the foundation trench, and the locating device and the fender posts (1) are fixed. The locating device of the drilling rod at the bottom of the foundation trench can save steel products and wall protecting slurry, the earth digging process is convenient and rapid, the construction period is reduced, and the precisions of verticality and a plane position of a mounting hole at the bottom of the foundation trench can be guaranteed.