Abstract: The wear of wire and the surface quality of silicon wafer under different wire speeds were studied.The micro and quantitative analysis of the used wire and silicon wafer was investigated by SEM and roughness instrument.The results showed that the smaller the wear of diamond wire with the wire speed increasing from 3.5 μm to 2.5 μm;;diamond wire cutting silicon materials for plastic and brittle mixed mode of removal of silicon surface profile showed a continuous groove, accompanied by a large number of scratches and pits, with the wire speed increasing the surface roughness of silicon wafer was gradually decreased, R_a、R_z and R_t decreased by 33.7%、37.8%、45.6%, the number of surface pits also gradually reduced.