The invention discloses a wing folding and unfolding mechanism for a cylindrical launching unmanned aerial vehicle. A torsion spring serves as wing surface expanding power, the mechanism is simple andreliable, and dependence on the environment is small; a bevel gear serves as a synchronous mechanism for the wing surface expanding process, the mechanism is simple and small in size, a wing surfacecan be unfolded completely and synchronously, and the flight reliability of the unmanned aerial vehicle is improved; a locking pin serves as a locking mechanism after the wing surface is expanded, thestructure is simple and small in size, reliability is good, a locking pin cap is designed, thus it is ensured that a wing can be rapidly folded after the unmanned aerial vehicle is retracted, and retracting of the unmanned aerial vehicle is competed; different balls serve as the contact form between motion interfaces, the friction resistance of the opening process is reduced, and rapidity of theopening process is ensured; and the overall folding mechanism is high in integration degree, simple, small in size, easy to assemble, and easy and convenient to operate, and the demands of the cylindrical launching unmanned aerial vehicle for wing folding are met.