LiNbO3 crystal was widely used as high precision and high-speed switching shutters because of its features of wide wave band, fast response, non-easy deliquescence and so on. In order to expand exposure time of optical switching of LiNbO3 to nanosecond field so as to make up defects of extant high-speed optical switching, theoretical principles of LiNbO3 were explained as optical switching, and its aspect ratio for multi-band lights was optimized and the feasibility of LiNbO3 as a nanosecond optical switching was verified. Experimental half-wave voltages match theoretical values well. Experimental results also show that optical signal has synchronous response to electric signal. Results verify the feasibility of LiNbO3 as a nanosecond optical switching and provide theoretical and experimental foundations for the manufacturing of the optical switching.