The invention provides a three-directional adjustment support. The three-directional adjustment support comprises an instrument support backboard, a parallel supporting arm and an instrument support pallet; the instrument support backboard is fixedly connected with a structure to be measured; the parallel supporting arm comprises two pedestals and two installation supporting arms; the pedestals are vertically connected with the installation supporting arms; each of the pedestals is provided with a first strip-shaped hole; the opposite sides of the two installation supporting arms are respectively provided with second strip-shaped holes; the pedestals are fixedly connected with the instrument support backboards through fixed bolts traversing through the first strip-shaped hole and the instrument support backboard; two side edges of the instrument support pallet are respectively provided with third strip-shaped holes; and the instrument support pallet is fixedly arranged between the two installation supporting arms of the parallel supporting arm through pallet installation screws traversing through the second strip-shaped hole and the third strip-shaped hole. The three-directional adjustment support can be used to realize convenient and fast three-directional adjustment of a plumb line displacement system arranged on the three-directional adjustment support, so the installation difficulty of the three-directional adjustment support is greatly reduced, and the maneuverability is improved.