  Many self-gravitating systems often show scaling properties in their mass
density, system size, velocities and so on. In order to clarify the origin of
these scaling properties, we consider the stationary state of N-body system
with inverse power law interaction. As a simple case, we consider the
self-similar stationary solution in the collisionless Boltzmann equation with
power law potential and investigate its stability in terms of a linear
symplectic perturbation. The stable scaling solutions obtained are
characterized by the power index of the potential and the virial ratio of the
initial state. It is suggested in general that the nonextensive system has much
various stable scaling solutions than those in the extensive system.
