Abstract: The radiation stability of separation systems for spent nuclear fuel reprocessing is an important problem to be solved before their practical use. In this work, the γ radiation effects on three commonly used heterocyclic N-donor ligands in ionic liquids(IB-BTP/［C₂mim］［NTf₂］, CA-BTP/［C₂mim］［NTf₂］ and CA-BTPhen/［C₂mim］［NTf₂］) were systematically studied by using Fourier transform infrared spectroscopy(FTIR) and ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry(UPLC/Q-TOF-MS). The changes in extraction performance of Eu³⁺ before and after irradiation were also compared. The results show that in the presence of ［C₂mim］［NTf₂］ ionic liquid, the order of the radiation stability of the three extracting agents is CA-BTP>IB-BTP≈CA-BTPhen; the main radiolysis products of the three systems are substitution products formed by heterocyclic N-donor ligands and radicals from ［C₂mim］［NTf₂］ ionic liquids(·CF₃, ·［C₂mim］⁺,  ·H, etc.). Even at an absorbed dose of up to 300 kGy, good extraction performances are still maintained.