The invention discloses a pneumatic folding apparatus of a variable-wing sweepback angle suitable for an aeronaval unmanned aerial vehicle. The folding apparatus comprises a folding wing support, a left wing driving assembly, a right wing driving assembly and a tucking-expansion transition assembly; and the left wing driving assembly and the right wing driving assembly are symmetrically installed at two ends of the folding wing support, and the tucking-expansion transition assembly is installed on the fixed plate of a frame assembly. The left and right wing driving assemblies are respectively provided with a self-locking composition, so when the wing driving assemblies arrive the tucking or expansion position, the positions of the wing driving assemblies can be fixed by inserting self-locking shafts into self-locking through holes, thereby the tucking and expansion positions of wings can be reliably maintained. The apparatus allows the tucking and the expansion of the wings to be controlled through adjusting the sweepback angles of the wings according to different work environments, so the gather adaptability of unmanned aerial vehicles in different fluid medium environments is increased.