Abstract：In this paper 1D P-wave characteristics are discussed when complex modulus is introduced into Biot equation. It is clear that thermal relaxation attenuation peak and Biot attenuation peak appear on both frequency and temperature domains. These two peaks change while temperature increases. The relaxation peak moves from low frequency side to high one，and Biot peak moves from high frequency side to low one. Also they change when frequency increases. The relaxation peak moves to high temperature side and Biot peak moves to low side. It is found that the combination of thermal relaxation and Biot mechanism leads to increment of wave velocity with two inflection points when its frequency rises. For the same reason，wave velocity decreases and then increases as temperature rises. The results are testified by experiments which are made by the authors. Some published experimental results are also well modeled in this way.
