An analytical study is performed to examine the influence of causally limited viscosity on the stability properties of an isothermal accretion disk. We find that the stability and propagating properties of three kinds of oscillation mode in the disk are different from those in the conventional viscosity case, if the viscosity is modified to follow causality. The viscous mode is still stable throughout the disk, but it is no longer a standing wave. It propagates inward with a damping rate proportional to the viscosity parameter α. The two inert...
