The invention relates to the field of medical instruments, in particular to a spiral close-range radionuclide radiotherapy device and a particle automatic loading assembly. The device comprises: a cylindrical bracket and a drainage tube; a spiral first groove is formed in the bracket, and the drainage tube is spirally mounted in the first groove; and a plurality of radioactive particles are installed in the drainage tube. The drainage tube is fixed on the outer periphery of the bracket, which can implant particles in a biliary tract to perform radiotherapy, and can expand the biliary tract sothat the bile can flow normally; the particle chain has the same flexibility, certain peristalsis and self-alignment function as the bracket, so that the particle chain can be stably placed at a specified location. When a fan-shaped pendulum block in the particle automatic loading assembly is oscillated and rotated, a process where a particle body at the gap is pushed out by a particle body push device, the particle body to be loaded in a particle box slides down to the gap to be clamped is performed circularly, and the particle body can be continuously fed and sent during the swinging of thefan-shaped pendulum block.