Provided are a cooling system with no refrigeration machine for an X-ray detector, and an X-ray imaging system using the system. The cooling system for an X-ray detector comprises: a cooling pipeline positioned on an X-ray detector; and a coolant transfer pipeline positioned at least partially in a support device of the X-ray detector and connected with the cooling pipeline to form a circulation loop, the circulation loop being provided with a circulating coolant therein. On the basis of the existing X-ray photography system, the configuration of a refrigeration machine can be removed from the cooling system, and the cooling of the detector can be realized with as few changes as possible, while meeting the temperature requirements of the normal operation of the detector and reducing costs.