In the present work, the characteristics of bulk wave propagation in an unsaturated porothermoelastic medium are studied taking into consideration of the thermal effect. The wave equations of thermoelastic waves of the problem are established by the mass balance equations, generalized Darcy law, momentum balance equations and generalized non-Fourier heat conduction law of the three-phase medium composed of solid, liquid and gas in unsaturated soils. The dispersion equations of bulk waves in unsaturated porothermoelastic media are derived using the potential functions. Compressional, thermal and shear waves with various speeds are analyzed numerically. It can be found that the thermal expansion coefficient has great influence on the wave speeds of P1 wave and thermal wave. The thermal conductivity only affects the speed of the thermal wave. A rise in the internal temperature of the unsaturated porothermoelastic medium can cause an increase of the wave speeds of compressional, thermal and shear waves.