A high-speed digital beam scanner based on electro-optic crystal switch array is developed. The scanner is composed of electro-optic beam splitter unit and deflection prism array. The electro-optic beam splitter unit is combined by LiNbO3 electro-optic switch and polarized beam splitter. The 3×3 rectangle beam scanning array is achieved by multistage cascade and space composition of electro-optic beam splitter units. The prism array behind beam scanning array can provide required angle deflection. The large-range far-field beam array scanning can be achieved. The beam scanning and tracking can be real-time controlled by programming. The systematical experiments confirm that the designed parameter of beam scanner agrees with the measured results.