Abstract: A theoretical model of 3D transient heat conduction in a multilayer cylinder irradiated by high power laser was developed in which the action of air flow around the exterior surface and the compatibilities of both temperature and heat transfer at the interfaces were taken into consideration. By using eigenvalue method and Bessel functions, the closed solutions of 3D transient temperature field in each layer of the cylinder were deduced. As a simple example, the axisymmetric transient temperature field was analytically computed and the effect rules of some parameters such as surface heat-exchange coefficient on the temperature field were obtained. The theoretical solutions of transient temperature field can be further used to analyze 3D thermo-mechanical effects of multilayer cylinders and can also be used as basis of modification of numerical models in related numerical simulations.