Two-dimensional ferroelectric materials can maintain stable polarization with atomic layer thickness, and they have a wide range of technological applications in transistors, resistive memories, energy collectors and other multi-functional sensors for highly integrated flexible electronics. Domain evolution should be considered when 2d ferroelectric material-based devices are applied in a radiation environment, which may induce radiation damage and performance degradation. In this work, we investigate the domain evolution and photodetection performance degradation of α-In2Se3 nanoflakes induced by the total dose effect of 60Co γ-rays. The phonon modes change with an increase in total dose, while the domain structure changes in α-In2Se3 based transistors. Domain evolution may be one of the main reasons for the photoresponsivity degradation of these transistors. This investigation can provide a solid base for future research, and immediate applications in 2d ferroelectric material-based devices can be contemplated.