Drive line shape for reflective magneto-optic spatial light modulator has been designed by computer simulation. A factor of 3 improvement in pixel switching sensitivity and power consumption, compared to the conventional reflective magneto-optic spatial light modulator, has been achieved by the use of wedge-shape drive line and a soft magnetic layer. A factor of 2 higher optical efficiency and a factor of 2 simpler fabrication process have been achieved by the use of drive lines that covers most of the surface of pixel and unpatterned insulator.