The invention relates to the technical field of upper limb rehabilitation training, and particularly discloses a rotary adjusting mechanism for upper limb rotating training. The rotary adjusting mechanism comprises a driving part, a body support, a rotary support, a transmission part and a rotating part. The driving part is fixed to one end of the body support. One end of the rotary support is fixed to the other end of the body support. The other end of the rotary support is connected with the output end of the rotating part. A steering wheel is connected into the rotary support. At least onetensioning wheel is arranged on the body support and can be adjusted. The output end of the driving part is fixedly connected with a belt wheel. The rotating part comprises a guide groove. The outputend of the rotating part can rotate along the guide groove. The transmission part is connected with the belt wheel, the tensioning wheel, the steering wheel and the output end of the rotating part. The rotary adjusting mechanism is simpler in structure, higher in bearing capacity, higher in flexibility, low in cost and small in size.