A yarn twisting device includes a frame and following components on the frame: a hollow shaft, in which a passage is provided for a yarn passing therethrough; a drive mechanism configured to drive the hollow shaft for rotation; a winding mechanism driven by the hollow shaft for rotation to rewind the twisted yarn; a speed reducing mechanism for transmission coordination between the hollow shaft and winding mechanism. The twisting device is in simple structure and less twisting tension, which is available for continuous twisting of a single yarn and combined twisting of multiplied yarns.