A modified BISQ (Blot/Squirt) model for wave propagation in low-permeability sandstone is developed by in-troducing the viscoelastic mechanism of a porous skeleton into Dvorkins model. The linear viscoelasticity of the Kelvin-Voigt constitutive law is employed to describe the stress-strain relation of a solid frame with clay while the ultrasonic waves propagate through the fluid-saturated sandstone. The phase velocity and attenuation of two p-waves are given based on the present BISQ model. The comparisons between numerical results and experimental data indicate that our viscoelastic model is more realistic and feasible for wave propagation in the low-permeability sandstone, especially with clay, than traditional BISQ models.