A mask structure for a deposition device includes first segments and second segments. The first segments are arranged in a direction surrounding a central axis and separated from one another. The second segments are disposed above the first segments. Each of the second segments overlaps two of the first segments adjacent to each other in a vertical direction parallel to an extending direction of the central axis. A deposition device includes a process chamber, a stage, and the mask structure. The stage is at least partially disposed in the process chamber and includes a holding structure of a substrate. The mask structure is disposed in the process chamber, located over the stage, and covers a peripheral region of the substrate to be held on the stage. An operation method of the deposition device includes horizontally adjusting positions of the first segments and the second segments respectively between different deposition processes.