The dual-phase-lag model has attracted increasing attention on account of its better heat transfer performance among many existing non-Fourier models. In this paper, we focus on the dual-phase-lag heat transfer process in a three-dimensional medium heated by a moving volumetric laser heat source. A series solution for the temperature distribution has been derived analytically by Green's function approach. According to this solution, the effect of the phase lag parameters and the heat source moving speed on the temperature distribution are investigated. The present results show the temperature variation not only on the top surface but also inside the medium, which can help us better understand the obvious non-Fourier temperature response of the three-dimensional medium.