Abstract: In order to break through the power restriction in IOC(intersatellite optical communication),the electrodes of MgO:LiNbO3 was optimally designed based on quasistatic conformal transformation theory in the background of IOC.The propagation of optical field with high input power was simulated.The effect of nonlinearity on modulator was analyzed and finally the maximum input power was determined.The research is significative for high power laser modulation field,such as IOC.