An unmanned aerial vehicle arm adjustment device for adjusting an unmanned aerial vehicle arm into a folding state or an extracting state with respect to a fuselage of the aerial vehicle includes: left and right curb plates connected to the fuselage; a rocking arm connected to the unmanned aerial vehicle arm, wherein one end of the rocking arm is articulated with the left and right curb plates, and a first engaging part is provided on the rocking arm; and a locking member articulated with the left and right curb plates, wherein the locking member is provided with a second engaging part for engaging with the first engaging part; wherein the locking member is adapted to rotate in a first direction to force the second engaging part to engage with the first engaging part so as to hold the rocking arm such that the unmanned aerial vehicle arm is in the extracting state; and wherein the locking member is adapted to rotate in a second direction opposite to the first direction to force the second engaging part to dis
