A height-adjustable arm structure includes a fixing base, a coupling block, a linkage mechanism, a damping element and a stopper. The coupling block is used to assembled with a machine module. The linkage mechanism includes a first end pivoted on the fixing base and a second end pivoted on the coupling block. The damping element is connected to the linkage mechanism and used to define the actuation range of the linkage mechanism. The stopper is movably disposed on the coupling block, and is selectively engageable with the second end, so as to stop the linkage mechanism一種可調整高度的支撐臂結構，包括一個固定基座、一個結合座、一個連桿機構、一個阻尼元件以及一個止動器。結合座用以與一個器械模組結合。連桿機構具有第一端以及第二端。第一端樞接於固定基座，第二端樞接於結合座。阻尼元件連接於連桿機構，用以限定連桿機構的作動範圍。止動器可動地設於結合座上，可選擇性地與第二端卡合，藉以止動連桿機構。
