High purity rare earth metals, such as samarium, ytterbium and thulium, have been prepared by vacuum reduction-distillation of each rare earth oxide with lanthanum metal. The rare earth metals of samarium and ytterbium with 4N-purity are prepared by direct vacuum reduction-distillation, and the purity of above metals is 99.99 wt.% and 99.993 wt.% respectively with respect to 75 impurities; there is a high concentration of reductant in thulium metal due to the higher reaction temperature and lower distillation velocity ratio of metallic thulium to lanthanum, so that the sublimation purification with lower temperature and high vacuum has been conducted, the purified thulium can be reach a high purity of 99.995 wt.% with respect to 75 impurities; the experimental results indicates that, the preparation of high purity reductant of lanthanum metal, especially of total amount control of metallic impurities, is the key step to obtain 4N-purity rare earth metallic samarium, ytterbium and thulium.