Abstract: An X-ray developable molecule, an embolism microsphere and preparation methods therefor, in the technical field of medical materials, are disclosed. The methods include preparing the X-ray developable molecule by reacting a compound with an amino group and an aldehyde, hemiacetal or acetal group with an iodobenzoic acid derivative, the X-ray developable molecule having an amide group; and/or reacting the X-ray developable molecule with a polyhydroxy polymer microsphere to prepare the X-ray developable embolism microsphere. The microsphere has X-ray developing and drug loading properties, and the methods of preparation and use are simple, so that a doctor can directly observe a body part containing the embolism microsphere using X-ray fluoroscopy. Intraoperative use is facilitated, the embolism extent is easy to determine, and complications in the intravascular treatment process are effectively avoided.