A model based on statistical method and elastic theory is presented to describe the wear mechanism of the silicon wafer surface during chemical-mechanical polishing. This model concerns the effects of applied pressure and relative velocity between the pad and the wafer on the removal rate during polishing and is capable of delineating the role of the mechanical properties of the slurry particles and the films to be polished. The removal rate is dependent on the elastic moduli of slurry particle and polished film. Comparisons with experimental data demonstrate the validity of the model for predicting relative removal rate for various dielectric films.