The invention discloses an autoclave-based creep age forming flexible frock, which comprises a vacuum bag, a bottom plate, a high frame, a low frame, nail battens, four gaskets, an adjusting stud, a fixed plate and an air exhaust hose, wherein the bottom plate is provided with a pin hole and a threaded hole; the high frame has a frame body consisting of two short high frames and two long high frames, and the vacuum bag is covered on the high frame and a piece to be formed; the low frame has a frame body consisting of two short low frames and two long low frames, the high frame is fixed at theperiphery of the low frame, and both the high frame and the low frame are fixed on the bottom plate; the nail battens are arranged on the bottom plate in parallel and fixed in the frame body of the low frame through side bolts; the four gaskets are arranged between the inner wall of the low frame and the nail battens; the lower part of the adjusting stud taps the screw thread which is used for forming the fixed plate with a screw thread pair; the central position of the fixed plate taps the screw thread hole which is used for forming the screw thread pair with the adjusting stud, the adjusting stud is fixed on the fixed plate, and then the fixed plate and the adjusting stud are fixed on the nail battens; and the air exhaust hose is connected to an air exhaust tube nozzle which penetrates and is fixed on the corresponding hole of the bottom plate and is hermetically connected through a silicon rubber gasket.