In order to study deeply the dependence of the velocity and attenuation of elastic waves in rocks on fluids,the distribution and viscosity of fluids must be considered.The authors introduced a gas pocket model to investigate the dependence of the velocity and attenuation of P waves on viscous fluid distribution,described the uniformity of fluid distribution with average bubble radius,calculated the curves which related velocities and attenuation with saturation under different bubble radius and pressure frequency and compared gas pocket model with effect fluid model.Because Gassmann equation weren't applicable under high-frequency pressure due to the local flow,the theoretical curves were corrected with the P wave and S wave velocities in dry and saturated sands.The saturation dependence of the P wave velocity and attenuation is measured and the attenuation was attempted to derive by using amplitudes of the peak frequency.The attenuation at dryness and saturation and the attenuation law from dryness to saturation are the same as those by spectral ratio method,but amplitude of the peak attenuation is different.By regressing measured velocity and attenuation with theoretical curves and computing the average radius of bubbles.It is considered that the saturation dependence of velocities and attenuation is related with pressure equilibration between gas and liquid in sands.