The invention discloses a linkage hollowed-out wing unit suitable for a flapping-wing air vehicle. The linkage hollowed-out wing unit suitable for the flapping-wing air vehicle comprises a rack, a driving device, a linkage device and a plurality of rotary wings which are sequentially arranged at intervals. The linkage device comprises a rocker, a reversing gear component, a gear connecting rod, a transmission gear and a vertically-mounted transmission rod. The designed wing unit is formed by arranging the multiple rotary wings at intervals, and the assembled wing unit is of a hollowed-out structure, so that when the air vehicle takes off, the contact area between the wing unit and air is small, the rising resistance borne by the air vehicle is small, the air vehicle can take off rapidly, and the flight efficiency is high; in addition, the wing unit is folded or unfolded through linkage control so that the flapping-wing air vehicle can obtain the optimal performance in different flight states; furthermore, the linkage device is adopted for synchronous deformation of the wing unit, the synchronization rate of deformation is high, and linkage control is stable and accurate; and the linkage hollowed-out wing unit is extremely suitable for the flapping-wing air vehicle of a small structure.