Technetium is an important fission product in the reprocessing process of spent fuels, and its determination is of great significance in nuclear chemistry and technology. However, nearly all related methods need a pretreatment step before measurement, the study proposed herein focused on the quantification of TcO₄⁻ in aqueous solutions simply using Raman spectroscopy with NO₃⁻ and water as internal standards without a sample preparation step. The relative intensity of TcO₄⁻ to NO₃⁻ (1047 cm⁻¹) and OH (1645 cm⁻¹) showed good linearity to the concentration of TcO₄⁻. The molar relative intensity was calculated for determination, and the predictions of these samples using both estimating methods were acceptable. The work also studied the behavior of TcO₄⁻ in a complex matrix, the results show that it is possible to use Raman spectroscopy for TcO₄⁻ quantitative determination in aqueous solution. The LOD and LOQ obtained is 0.42 mmol L⁻¹ and 1.39 mmol L⁻¹, respectively.