Membranes have been widely used in low-level radioactive wastewater (LLRW) treatment and are under irradiation as a result of radioactive nuclides present in the wastewater, which may cause damage to the membranes and weaken their performances. Irradiation-induced material property changes of several organic membrane matrices and modifiers at different gamma irradiation doses were investigated in this work. The organics and membrane samples were irradiated using a 60Co source at a range of irradiation doses of 0 to 100 kGy. The effects of irradiation on these materials were detected using Fourier transform infrared spectroscopy spectra, ultraviolet spectra, and ion chromatography (used to detect membrane leakage). The results indicated that chain scission and cross linking occurred simultaneously in the membrane matrices, while the modifiers tended to polymerize during the irradiation process. As the irradiation dose increased, the chain scission and polymerization became more significant. The polyamide membrane was observed to be more irradiation tolerant in comparison with the other membranes used in this study. In regard to the modifiers, polyvinyl alcohol and 2,3-epoxypropyl trimethyl ammonium chloride showed significant structural changes at an irradiation dose of 2 kGy and polyetherimide and methyl methacrylate at an irradiation dose of 100 kGy, while chain scission was not detected in the other modifiers at irradiation doses of 2, 10, and 100 kGy, indicating that they remained relatively stable at these irradiation doses. These findings provide useful information for the application of membrane technologies in treating LLRW.