Abstract: The determinations of Pu(Ⅳ) and nitric acid play a significant role in the nuclear fuel reprocessing plant to control process accurately and timely. By scanning near infrared absorptive spectra with the spectroscopic instrument and processing the spectra data with PLS method, a simultaneous and fast determination method for Pu(Ⅳ) and the nitric acid in organic feed solution of nuclear fuel reprocessing was successfully developed. For the measurements of Pu(Ⅳ) and nitric acid in organic solutions, the concentration measurement ranges of Pu(Ⅳ) and the nitric acid are 0.15-15 g/L and 0.05-0.80 mol/L, respectively, which almost cover most of analytical processing point of nuclear fuel reprocessing. One sample was measured six times, the relative standard deviation of nitric acid is less than 5%, and that of Pu(Ⅳ) is less than 2%. All of the results are successfully examined by t test. The recoveries of Pu(Ⅳ) and nitric acid are 95%-103% respectively.