A kind of P204 extraction and separation method for preparing 5N neodymium of the present invention, with P204 as extraction agent, neodymium chloride as feed liquid, comprises 7 steps, wherein 3 separation steps and 4 auxiliary steps; 3 separation steps are respectively PrNd / NdSm full-load fractionation extraction and separation section, Pr / Nd quasi-fractionation extraction and separation section, Nd / Sm fractionation extraction and separation section, and four auxiliary process steps are concentration section, acid extraction section, stripping section and rare earth saponification section. Finally, 5N neodymium products, praseodymium-rich products and samarium-rich products are obtained, among which the relative purity of the neodymium product phase is as high as 99.999%-99.9995%, and the yield is as high as 91.64%-94.40%. Compared with the preparation of high-purity neodymium products by non-solvent extraction methods such as resin column chromatography and ion exchange, the present invention has the advantages of high purity of neodymium products, high yield of neodymium products, large production scale, low consumption of chemical reagents, and easy automation , easy to operate, low production cost, conducive to industrial production and other advantages.