Surface acoustic wave (SAW) gyroscopic effect is analyzed when a piezoelectric half-space rotates, and the change form of angular speed verus the wave velocity is obtained. Then the acousto-optic coupling wave equation is discussed, and the formula relationship of angular speed and the diffraction efficiency is gotten in acousto-optic coupling situation. The optimization design to the acousto-optic gyroscope′s structure is carried on according to this relationship. The optimization design indicates that X cuts Y propagating and Z cuts Y propagating LiNbO3 crystal have the biggest scale factor, the sensitivity is usually the highest when the gyroscope rotates along SAW propagating direction, and the accuracy of this design is 2.06°/h, which is 2 orders of magnitude higher than that of normal SAW gyroscope.