Abstract: In order to study the temperature variation of the laser welding process of carbon fiber reinforced composite and aluminum alloy, this paper took 6061 aluminum alloy and carbon fiber reinforced Nylon 66 composite (CF/PA66) as the research object, established the finite element model based on heat conduction, and used SYSWELD software to conduct numerical simulation of the laser welding process of the two materials. The accuracy of the model was verified by experiments. On this basis, the influence laws of laser power, welding speed, lap width, cooling conditions and tooling thermal conductivity on the joint temperature field were studied. It is found that the size of aluminum alloy molten pool and the melting zone of PA66 resin increase with the increase of laser power and decrease with the increase of cooling rate. Under the same process parameters, the material lap size has no effect on the maximum melting width of interfacial resin. The water cooling condition can significantly reduce the melting pool size and the melting capacity of PA66 resin. The reduction of melt pool size and melting amount of PA66 resin is more significant.