A medical radiation device, including a main frame, and a radiation assembly and an imaging assembly respectively located at an end of the main frame. After an imaging scan is completed and diseased tissue positioning images are taken, a patient is directly moved to the other end of the main frame to allow the radiation assembly to perform a radiation treatment to improve the efficiency of the radiation treatment after the completion of diseased tissue positioning, and effectively reduce movement of the patient when the patient is being moved for radiation treatment after the imaging assembly completes diseased tissue positioning, thus reducing a positioning error of the diseased tissue caused by too much movement.