The invention discloses a radioactive particle chain connected by a controlled degradable magnesium and magnesium alloy pipe, which belongs to the field of medical appliance implanted to an organism. The radioactive particles 2 are connected by the controlled degradable magnesium and ultra-thin magnesium alloy pipe 1 at a certain interval. In the invention, the radioactive particle plays a treatment role, and the magnesium and magnesium alloy pipe acts as a connecting material. Due to controllable rapid degradation characteristics, the radioactive particle chain can ensure uniform distribution of particles and prevent particles from wandering. The chain is degradable after being implanted for one week to one month, so that the interval between particles can be reduced with the shrinking of a tumor to uniformly distribute the particles within a lesion. The radioactive particle chain of the invention can be used for treating extensive diseases, which mainly comprise intracranial tumor, nasopharyngeal carcinoma, oropharyngeal cancer, tongue cancer, neck metastases, lung cancer, breast cancer, pancreatic cancer, cholangiocarcinoma, liver cancer, prostate cancer, gynecological tumor, soft tissue and bone tumor.