The invention provides a radioactive source delivery device for a nuclide post-loading treatment machine, which includes: a real source driving mechanism, a false source driving mechanism, a source storage lead bag, a source tube, and a source detection mechanism; the peripheral equipment is a source applicator ; Among them, both the real source drive mechanism and the false source drive mechanism include: stepper motor, drive disc, drive belt, four pulleys, steel wire rope, steel wire storage pipeline, micro switch, access guide nozzle, delivery guide nozzle, steel wire Tail detection device, channel obstruction detection device, belt tensioning device; the key point of the present invention is that the radioactive source steel wire rope is always in the storage pipeline, without multiple coils on the driving disc, and the source jamming failure will not occur. Moreover, the invention has the characteristics of safety and reliability, convenient installation of radioactive sources, and simple debugging and maintenance.