Took into consideration the coupling effect of thermo, hydraulics and mechanics, a set of thermo-hydro-mechanical coupled wave equations for fluid-saturated soil are developed. In these wave equations, the -wave in solid phase and -wave in fluid phase are coupled into -wave in fluid-saturated soil by the assumption that the temperature of the solid phase is equal to the temperature of liquid phase at the same position. The dispersion equations for the thermo-elastic wave, which can be degraded to the equations for elastic wave in fluid-saturated soil, are derived from the above equations by introducing four potential functions. Then, these equations are solved numerically. The characteristics of wave phase velocity, attenuation and the effect of thermal expansion, initial temperature and porosity, etc., on phase velocities of -, -, and -wave are discussed. As a reference, the characteristics of the propagation of elastic waves in fluid-saturated soil are also studied. The computation results show that (1) the phase velocity of -wave obtained by the theory of thermoporoelascity (THM) is faster than that by the theory of poroelasticity (HM); (2) the attenuation of -wave obtained by either the theory of THM or HM are consistent; (3) the dissemination characteristics of -wave are almost consistent; (4) the phase velocity of -wave is the slowest among the three compressional waves; and (5) The attenuation versus frequency characteristic of -wave is similar to that of P-2-wave.