Abstract: This paper presents a method for measuring ⁹⁹Tc from reductive medium in PUREX process. Taking 1BP as an example, the measurement process includes removal of plutonium, oxidation of technetium, extraction of technetium, and liquid scintillation measurement. The plutonium in the sample is first adjusted to valence of +4, and extracted with 1-phenyl-3-methyl-4-benzoylpyrazolone-5(PMBP). Then, the technetium is oxidized to +7 valence with potassium dichromate at 50 ℃. After that, the sample is added to potassium carbonate solution, and then technetium is quantitatively extracted with 2,4,6-trimethylpyridine in the alkaline medium, and measured by liquid scintillation method. With this method, technetium from reductive medium of PUREX process can be analyzed within 20 minutes, and the relative standard deviation is 0.6%(n=3).