  We investigate an interacting fermion model with boundary potential by using
Bethe ansatz method. The ground state properties of the system and the boundary
effect are discussed. It is found that attractive boundary potential leads to
the boundary bound state. An interesting phenomenon is that the slidding
collective charges in a periodic system, which is formed due to the attractive
interaction among the fermions, will be pinned around the boundary, as long as
the negative boundary potential is strong enough.
