Differential spinning frame, wave-shaped siro compact spinning yarn and preparation method of wave-shaped siro compact spinning yarn

The invention discloses a differential spinning frame, a wave-shaped siro compact spun yarn and a preparation method of the wave-shaped siro compact spun yarn. The differential spinning frame is sequentially provided with a first roller, a second roller, a third roller, a negative pressure special-shaped air suction pipe and a fourth roller in the production proceeding direction, the differential spinning frame further comprises a main motor, and the first roller, the second roller and the third roller are in transmission connection with the main motor. The third roller and the fourth roller are in transmission connection through a carrier gear, the third roller comprises a first thick section and a first thin section in the axis direction, and the fourth roller comprises a second thick section and a second thin section in the axis direction. The third roller and the fourth roller are designed into thick and thin sections, and the rotating speed of the third roller and the rotating speed of the fourth roller