The invention discloses a yarn drying device for spinning and a drying operation method thereof. The drying device comprises a long flat box, a square opening, a fixed pulley, a first inflatable shaft, a traction plate, a rectangular frame, an air cylinder, a first motor, a protective cover, a side supporting plate, an exhaust fan, wire guide wheels, a T-shaped block, a strip-shaped sliding groove, an L-shaped plate, a second motor, a belt wheel, a long screw, a second inflatable shaft, a square strip hole, electric heating wires and triangular belts. The drying device is advantaged in that the drying device is reasonable in structural design, seven wire guide wheels are distributed in a staggered traction manner, to-be-dried yarns can be distributed in the drying structure in a broken line shape, flexible adjustment is achieved, the length of the yarn in the drying structure is increased or decreased, hot air in the drying structure can flow upwards from the bottom, the drying effectis achieved, the dried yarn is wound together through the rotating first air expansion shaft, the connected traction plates are driven by the started air cylinder to move outwards, the effect of drying and winding at the same time is achieved, and that the yarn can still be normally wound when the diameter of a yarn roll is gradually increased can be guaranteed.