The invention discloses a separation section for preparing 5N terbium through a solvent extraction method. P507 serves as an extraction agent, and 2N5-3N5 terbium chloride serves as feed liquid. Eight steps are included and include three separation steps and five auxiliary steps. The three separation steps include the GdTb/TbDyHoY separation section, the Gd/Tb separation section and the Tb/DyHoY separation section. The five auxiliary steps include the concentration section, the acid extraction section, the rare earth saponification section I, the reverse extraction section and the rare earth saponification section II. Finally, a 5N level terbium product with the relative purity being 99.9990%-99.9996% is obtained, and the productive rate of the 5N level terbium product reaches up to 95.46%-98.75%. The separation section has the beneficial effects that the purity of the terbium product is high, the productive rate of the terbium product is high, the production scale is large, chemical reagent consumption is low, operation is easy and convenient, and the production cost is low.