The invention discloses a wing folding-unfolding mechanism for a small unmanned aerial vehicle with folding wings. The wing folding-unfolding mechanism comprises an upper cover plate (1), a spring drive mechanism (2), a manual unlocking rod (3), a vertical wing rib plate (4), a rotary plate (5), a lower cover plate (6), a front vertical plate (7), a steering engine (8), a middle vertical plate (9), a steering engine unlocking link mechanism (10), a small vertical plate (11), a right vertical plate (12), a locking hook mechanism (13) and a rotary shaft (14). By virtue of the deformation of a slider-swing rod mechanism, the wing folding-unfolding mechanism has a self-locking function, and is simple in structure and reliable in action; drive force comes from a spring, the change rule of output force is simple, and the wing folding-unfolding mechanism is simple to design and produce, low in cost and convenient to use, and can be reused; and the steering engine unlocking link mechanism is designed to be of a unidirectional stressed type, and thus the conversion process from an unfolding state to a folding state is simplified.