Abstract：The experimental results of dry and fluid-saturated sedimentary rocks，metamorphic rocks，and igneous rocks are compared using different methods and frequency bands. It is shown that in low frequencies，the attenuation and dispersion of dry rocks are much smaller than those of saturated rocks，which can be negligible. The attenuation peaks of saturated rocks vary with the viscosity of fluid. At acoustic frequencies，there are large differences in the stress-time curves between dry and saturated rocks. The hysteretic effect of fluid causes dispersion and encumbrances the unloading so that the curve falls more slowly. As the viscosity increases，the hysteretic effect increases，which demonstrates the unique properties of viscoelastic materials. The global stress-strain curves show that the strength of dry rocks is larger than that of saturated rocks. The strength of parallel stratifications is larger than that of vertical stratifications，which makes the rocks anisotropic. The anisotropy of dry rocks is very small，while it is enhanced by the fluids. At low saturation，the moduli and velocities of waves decrease as the saturation increases. However，at high saturation，the moduli and velocities increase with saturation. The moduli and velocities remain steady and unchanged at medium saturation area. These experimental results can be explained by the fact that in PM model，the microscopic nonclassical nonlinear units are easier to be activated，leading to the increase of nonlinearity and diagonal density of PM space. These mentioned phenomena caused by the effect of fluids threaten some major rock projects so that attentions should be paid.
