Abstract: In order to verify the feasibility of using fiber laser for fuel assembly disassembly and fuel rod cutting, the cutting quality of UO2 pelletstainless steel cladding composite structure with great difference in thermal properties and fuel rod pellet cutting quality were studied. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Xray diffraction (XRD) were used to characterize the microstructure of crosssection of UO2 pellets. And the effects of laser cutting process on the surface morphology, element composition and phase of uranium pellets were studied. The results show that fiber laser can be used to cut nuclear fuel rod which is composed of UO2 pellets and 316Ti cladding. Although the laser cutting process leads to a lot of micropores and fragments on the cutting section, it doesn’t cause the phase transformation of UO2. This study shows that the fiber laser can be used in the cutting of nuclear fuel rod which is composed of UO2 pellets and 316Ti cladding. Through the subsequent radiation shielding protection of the laser cutting system, the fiber laser can be applied to the spent fuel assembly disassembly and spent fuel rod cutting.