Akstraet-The effect of finite speed of heat propagation on the orientations of crack initiation from a moving heat source is studied analytically in this work. The thermal wave model is employed and the Neuber-Papkovich representation for the thermoelastic displacement potential is modified accordingly to account for such an effect. The modified term appears as the highest order differential in the resulting equation and the stress field as well as the orientations of crack initiation significantly deviate from those predicted by the thermal diffusion model. A thermal Mach number M defined as the ratio of the speed of the moving heat source to that of the heat propagation in the solid is introduced in the formulation to character&e both the thermal and the mechanical fields. Both the maximum circumferential stress and the strain energy density criteria are considered in the analysis. In the subsonic range with M < 1, the emphasis is placed on the difference of the results predicted by the two criteria. While at the transonic (44 = 1) and in the supersonic (M > 1) ranges, special considerations are given to the field singularities induced by the thermal shock waves. Also, as the thermal Mach number increases, the evolutions of the heat affected zone and the thermally undisturbed zone in the physical domain are discussed.