Abstract: A spectrometric method is described for direct determination of the abundanceof ~(235)U in recovered U_3O_8. The photography-plate box in the model ИСП-51spectrograph is improved, photograph-plates has replaced 135 films and the U_3O_8sample is excited by a direct current arc. A similar way to single standardcomparative method for mass spectrometric analysis is used to calculate isotopeabundance, The ~(235)U abundance ranges from 0.93% to 90.7%(atomic percent) andthe precision (relative standard deviation) is ±(2.0-9.3%). The results abtainedapproximate the data by mass spectrometry.