Abstract: In order to improve the properties of poly (butylene succinate) (PBS)-based composites and reduce the production cost of PBS-based composites, the wheat straw powder/PBS-poly (butylene adipate-co-terephthalate) (PBAT) composites were prepared by melt-blending method, and then the composites were irradiated by ⁶⁰Co-γ rays. The effects of radiation modification on mechanical properties, thermal stability and thermal deformation temperature of wheat straw powder/PBS-PBAT composites were studied. FTIR and SEM were used to observe the structure and fracture surface morphology of the composites before and after the radiation treatment. Results show that when the triallyl isocyanurate (TAIC) content is 1wt% and the composites are irradiated by 30 kGy dose, the tensile strength, bending strength and impact strength are increased by 20%, 23.5% and 6.5% respectively. The pyrolysis rate of the composites is improved by radiation modification, its thermal deformation temperature rises by about 11℃, and the cohesiveness is strengthened between composite components.