The invention discloses a self-locking 90-degree full-wing variable sweepback transmission mechanism. The transmission mechanism comprises a connecting rod assembly A, a connecting rod assembly B, a wing root rotation assembly A, a wing root rotation assembly B, a driving assembly, an upper connecting plate, a lower connecting plate and four props, wherein the upper connecting plate, the lower connecting plate and the four props form a bearing rack body; the connecting rod assembly A and the wing root rotation assembly A form a left wing motion part; and the connecting rod assembly B and the wing root rotation assembly B form a right wing motion part. The transmission mechanism of the invention drives a plurality of levers to reciprocate by using a screw rod, so that wing support bars connected to the two symmetrical wing root rotation assemblies can move forwards or backwards by 90 degrees.