A method for distillation of sulfur for preparing radioactive phosphorous nuclide includes the steps of: charging powdered sulfur into a target tube designed to have an upper and a bottom neck; degassing the target tube to form a vacuum therein, followed by heating the upper neck to seal the target tube; irradiating neutrons into the sealed target tube to produce radioactive phosphorous nuclide; heating the distillation zone to distill the remaining unreacted sulfur; and cleaving the target tube at the bottom neck to separate the distillation and the cooling zone from each other, the separated zones containing the radioactive phosphorous nuclide and the unreacted sulfur, respectively, whereby the radioactive phosphorous nuclide of high purity can be prepared while the sulfur can be recovered at high efficiency.