Based on the diffusion equation of prorous-thermoelastic waves presented by the authors, the problem of reflection of plane p-wave on a free interface was investigated and the expressions of the reflection coefficient were derived. Then, the effect of thermal expansion coefficient of the porothermoelasticity on the propagation speed of p₁ in the medium was discussed firstly. Furthermore, through the analysis of the effect frequency, incidence angle on the amplitude characteristics of reflection wave, the drainage and no drainage conditions were considered, , and the effect of interfacial pervious and impervious conditions was also discussed. It is shown that the thermal physical parameters have a certain effect on the propagation of thermoelastic waves, and such parameters as frequency, incidence angle and surface drainage conditions are factors greatly affecting the reflection amplitude of two types of compression wave, shear wave and thermal wave.