The invention provides a mechanical arm and a surgery robot. The tail end of the mechanical arm is used for grasping a medical apparatus. The mechanical arm comprises a first rotating joint, a first swinging joint, a second swinging joint, a second rotating joint, a moving joint, and an autorotation joint for realizing the autorotation of the medical apparatus, which are sequentially distributed from the near end to the far end. According to the mechanical arm disclosed by the invention, through the cooperation of the six joints, the adjustment of the space position and the posture of the medical apparatus can be realized, and the six joints can move around a long-distance movement center. Compared with the prior art, the mechanical arm disclosed by the invention is small in whole dimension, light in quality, convenient to mount and use; and in addition, through the moving joint and the autorotation joint, an endoscope is driven to move and autorotate, so that a doctor can convenientlyand independently complete surgery operations and endoscope grasping, the difficulty of the surgery operations is reduced, and the waste of human resources is avoided.