Chemical mechanical polishing (CMP) is a key process widely used in semiconductor manufacturing industry to provide local and global planarity of silicon wafers.In this talk, the mechanisms of material removal in CMP process are investigated in detail by the smoothed particle hydrodynamics (SPH) method where an new, efficient and parallel neighbour search method based on plane sweep algorithm is proposed at the same time.The feature-scale behaviours of slurry flow,rough pad, wafer defects, moving solid boundaries, slurry-abrasive interactions and abrasive collisions are modeled and simulated.