The invention discloses an adjustable structure, which comprises a first adjustment piece and a second adjustment piece, wherein the first adjustment piece comprises a first slide way in which a first main slotted hole is arranged; the two ends of the first main slotted hole are provided with a plurality of pairs of first main positioning openings; the second adjustment piece comprises a first sliding part which is provided with a first pressing part; the two ends of the first pressing part comprise a pair of first positioning parts; the first sliding part is arranged in the first slide way in a sliding way; and when the first pressing part is positioned in the first main slotted hole, the pair of first positioning parts is selectively clamped in one of the plurality of pairs of first main positioning openings.