Abstract: The corrosion behavior of stainless steel in acidic radioactive waste solutions, together with its contamination mechanisms involving radionuclides such as uranium (U), strontium (Sr), and cesium (Cs), is recognized as a critical issue in nuclear waste treatment systems. In such environments, stainless steel equipment is continuously exposed to nitric-acid-based waste liquids containing multiple fission products, where corrosion, radionuclide adsorption, and co-precipitation occur and ultimately can lead to the formation of persistent contamination layers. Although the corrosion of stainless steel in nitric acid solutions is widely investigated, the coupled contamination mechanisms between U, Sr, and Cs and stainless-steel surfaces under radioactive waste storage conditions remain insufficiently understood. Therefore, the contamination behavior of 304L stainless steel in simulated acidic radioactive waste solutions containing U, Sr, and Cs was investigated in this study. Test specimens of 304L stainless steel were immersed in mixed nitric acid solutions containing U, Sr (non-radioactive isotope), and Cs (non-radioactive isotope) at 40 ℃ and 60 ℃ with acidities of 3-12 mol/L HNO₃ for immersion periods ranging from 7 to 60 d. Corrosion morphology, phase composition, and surface chemical states were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Based on these analyses, the corrosion behavior was evaluated and the radionuclide contamination mechanisms were examined. The results indicate that the corrosion severity increases with temperature, nitric acid concentration, and immersion time. Uniform corrosion is observed under mild conditions, whereas severe intergranular corrosion occurs under extreme conditions such as 60 ℃ and 12 mol/L HNO₃ for 60 d. XRD analysis shows that the δ-ferrite diffraction peak gradually diminishes with increasing acidity, indicating continuous dissolution of the matrix. XPS analysis further reveals that the formation of contamination species is closely associated with the corrosion process: Sr and Cs are present as co-precipitates with corrosion-released Cr⁶⁺, while U exists mainly in the forms of UO₂, UO₃, and adsorbed \textUO_2^2+ . Based on these findings, the contamination process can be divided into three stages: The initial stage, where initial physical adsorption occurs on the intact passive film; The second stage, U, Sr, and Cs selectively accumulate in the corroded area; The third stage, extensive diffusion accompanied by a large amount of co-precipitation occurs in the microstructure of severe corrosion. These insights provide an improved understanding of radionuclide retention on stainless steel in acidic radioactive waste environments and are expected to offer theoretical guidance for the optimization of subsequent decontamination technologies.