The invention relates to a treatment bed rotating transmission device, in particular to a treatment bed rotating transmission device used for a large medical device. The transmission device has high location accuracy and a self-locking function. The treatment bed rotating transmission device comprises a base, a transmission device and a support device. The transmission device comprises a worm wheel and a worm, the worm wheel is fixed on the base, the worm is meshed with the worm wheel and is arranged on a box, one end of the worm is connected with a speed reducer, the speed reducer is connected with a servo motor, the inner side of the worm wheel is connected with a center shaft through a second rolling bearing, the center shaft is fixedly connected with the box, and the support device is fixed on the box. The treatment bed rotating transmission device is provided with a servo system having a quick response capability and has high treatment bed rotating angle control precision, and data are read accurately; the transmission device performs back clearance elimination treatment and has a self-locking function, motor damage is avoided, a treatment bed runs stably, and safety is high.