The diamond wire saw powder composition and its silicon oxides were analyzed by X-ray diffraction analysis (XRD), X-ray fluorescence spectrum analyzer (XRF) and Fourier transform infrared spectrometer (FT-IR). The possible reaction process for alloying between aluminum and diamond wire saw powder was analyzed, and its thermodynamics were determined by HSC Chemistry 6.0 software. The kinetics process of aluminum thermal reduction of SiO2 was discussed, and the Al?Si alloy preparation by using diamond wire saw powder with aluminum was experimentally investigated. The results showed that the diamond wire saw powder melted with aluminum in different mole proportion during the alloying process at the temperature range of 800~1600℃ with the influence of electromagnetic stirring. Meantime, SiO2 impurities can be reduced to Si during aluminum thermal reduction. The apparent activation energy was 364.1 kJ/mol, while the reaction order was 0.91. Finally, phase composition of alloy and slag were analyzed by EPMA, XRD, and the results were in agreement with the thermodynamic and kinetic analysis. This work provided a new idea for effectively solving the problem of silicon waste recovery and utilization during the photovoltaic industry.