The invention relates to the technical field of medical equipment and particularly discloses a blood irradiation instrument based on X rays. The blood irradiation instrument comprises a high-voltage generator, an X-ray tube cooling system, an X-ray tube, an irradiation control and management system, a blood-bag storage and rotating mechanism and a body, wherein the high-voltage generator, the X-ray tube cooling system and the irradiation control and management system are all arranged on the body; the body is internally provided with a protective chamber; in the sealed protective chamber, the X-ray tube can emit 360-degree ring-shaped and conical X-ray beams to irradiate blood in a cavity body on a disc bracket; since a motor drives the cavity body to rotate around the X-ray tube, the blood and biological tissues and the like can receive uniform irradiation dosage and good uniformity of irradiation is ensured; the irradiation control and management system controls the high-voltage generator to drive the X-ray tube to carry out irradiation, so that the irradiation dosage can be controlled; and all the irradiation is in the protective chamber, so that good safety is ensured, other protective means are not needed and the medical cost is reduced.