In order to better understand the grinding mechanism, the rough, semi-fine and fine ground silicon wafer subsurface damage models are experimentally investigated with the aid of advanced measurement methods. The results show that the rough ground wafer subsurface damage model is composed of large quantity of microcracks with complicated configurations, high density dislocations, stalk faults and elastic deformation layer. Among them microcracks, dislocations and stalk faults are dominant. Apart from the above damage, the amorphous layer and polycrystalline layer (Si-I, Si-III, Si-IV and Si-XII) exist in the semi-fine ground and fine ground wafer subsurface damage models. The amorphous layer depth firstly increases from rough grinding to semi-fine grinding and then decreases from semi-fine grinding to fine grinding. The damage model can be divided in severe damage part and elastic deformation part with high stress. When the material is removed by ductile mode two parts are all small and the ratio of second part is relatively great.