Disclosed are an installation case for a radiation device, an oil-cooling circulation system and an X-ray generator which belong to the technical field of X-ray generator. This disclosure aims to solve the technical problems existing in the conventional X-ray generator, that is, the conventional X-ray generator provides bad sealing, the weight of the case body of the conventional X-ray generator is heavy, and the leakage dose of the X-ray in the conventional X-ray generator is large. The installation case for a radiation device according to this disclosure comprising a case body and a collimator fixedly connected with the case body, the collimator being provided with a beam exit aperture and the case body being provided with a beam exit opening, the installation case for a radiation device further comprises a shielding device provided within the case body, the collimator and the shielding device are integrally formed, or the collimator and the shielding device are two separate parts and are fixedly connected with each other; each layer of the shielding device is provided with a ray exit aperture, and the ray exit aperture, the beam exit aperture and the beam exit opening are coaxial. The X-ray generator according to this disclosure comprises the oil-cooling circulation system according to this disclosure. The installation case for a radiation device according to the disclosure provides improved sealing and ray leakage-proof performance.