Making the surface of insulation layer flat using CMP (Chemical Mechanical Polishing) is important for producing IC (Integrated Circuit). Although simulations of CMP have been carried out using various methods to clarify the effect of working conditions, behavior of slurry including polished debris has not been clarified yet. In this paper, simulation of CMP is carried out using SPH (Smoothed Particle Hydrodynamics) in which slurry including polished debris can be handled. The behavior of polishing slurry and pad damage caused by the slurry are analyzed for various strength of interaction between polished debris and for various ditches on a polishing pad. It is shown that polished debris become bigger in the neighborhood of polished surface when interaction between polished debris becomes stronger. On the other hand, when interaction becomes weaker on ditches become shallower, the number of small polished debris that circulate within the ditches increases. The polishing pad is damaged rapidly for strong interaction between debris and for shallow ditches on a polishing pad.