A rope transmission device for driving a limb fixing assembly, the rope transmission device comprising: a device main body; a transmission assembly, wherein the transmission assembly is provided to the device main body; a rope winding shaft, wherein the rope winding shaft is rotatably connected to the transmission assembly, and at least one continuous rope winding spiral groove is provided along a peripheral edge of an outer wall of the rope winding shaft, the rope winding shaft having an inner end proximal to the transmission assembly and an outer end remote from the transmission assembly; an oscillating piece for driving the limb fixing assembly, wherein the oscillating piece is provided on the device main body in such a way that an oscillating shaft around which the oscillating piece oscillates is collinear with a rotation shaft of the rope winding shaft; two ropes, wherein one end of one of the ropes is fixed to the rope winding shaft, and it is partially wound in a portion of a groove near the inner end of the rope winding spiral groove of the rope winding shaft, and the rope is further fixed to one end of the oscillating piece around a circumference that the oscillating piece oscillates; after one end of the other rope is fixed, it is partially wound in a portion of the groove near the rope winding spiral groove, and the rope is fixed to the other end of the oscillating piece around the circumference that the oscillating piece oscillates; charaterised in that: the rope transmission device comprises two rope tighteners, and the oscillating piece has a circular arc outer wall portion and at least one radial connecting portion connected to the circular arc outer wall portion, the radial connecting portion being provided to be rotatably mounted to the device main body about the oscillating axis, wherein each of the ropes is respectively connected to one rope tightener in a way that can be tightened in a tangential direction tangential to the circular arc outer wall portion. a device main body; a transmission assembly, wherein the transmission assembly is provided to the device main body; a rope winding shaft, wherein the rope winding shaft is rotatably connected to the transmission assembly, and at least one continuous rope winding spiral groove is provided along a peripheral edge of an outer wall of the rope winding shaft, the rope winding shaft having an inner end proximal to the transmission assembly and an outer end remote from the transmission assembly; an oscillating piece for driving the limb fixing assembly, wherein the oscillating piece is provided on the device main body in such a way that an oscillating shaft around which the oscillating piece oscillates is collinear with a rotation shaft of the rope winding shaft; two ropes, wherein one end of one of the ropes is fixed to the rope winding shaft, and it is partially wound in a portion of a groove near the inner end of the rope winding spiral groove of the rope winding shaft, and the rope is further fixed to one end of the oscillating piece around a circumference that the oscillating piece oscillates; after one end of the other rope is fixed, it is partially wound in a portion of the groove near the rope winding spiral groove, and the rope is fixed to the other end of the oscillating piece around the circumference that the oscillating piece oscillates; charaterised in that: the rope transmission device comprises two rope tighteners, and the oscillating piece has a circular arc outer wall portion and at least one radial connecting portion connected to the circular arc outer wall portion, the radial connecting portion being provided to be rotatably mounted to the device main body about the oscillating axis, wherein each of the ropes is respectively connected to one rope tightener in a way that can be tightened in a tangential direction tangential to the circular arc outer wall portion.