To investigate the temperature-field distribution of UO₂ ceramic pellets-316Ti stainless steel composite structure during laser cutting processes, considering the relationship between thermal physical parameters and the temperature of materials, we simulated the laser cutting process for the composite structure using ANSYS finite-element software. User defined function loading and compiling of laser heat source C language program was realized using the Fluent module of ANSYS. The temperature distribution cloud maps were studied at different cutting parameters. The results show that temperature distribution is mainly expressed as comet-like state. Maximum temperature is concentrated at the center of the cutting heat source, and it increases with increasing laser power and decreasing cutting speed. When the laser power is too low or cutting speed is too high, the workpiece due to insufficient heat input will not be cut through. If the laser power is too high or cutting speed is too low, the kerf width widens due to the lager material melting area. The simulation results can be used to optimize the parameters of the actual cutting process.