In　this　paper,　ways　to　design　LiNbO3　anisotropic　acousto-optic　device　based　on　beam　steering　theory　are　studied.　The　accurate　design　parameters　for　plane　configuration　and　step　configuration　are　systematically　calculated.　The　result　shows　that　anisotropic　acousto-optic　device　using　LiNbO3　crystal　can　realize　optimum　design　with　beam　steering　theory;　it　can　gain　wide　3　db　bandwidth　and　high　diffractive　efficiency　simultaneously.　The　research　also　shows　that　acousto-optic　device　designed　in　step　configuration　gains　a　higher　energy　utilization　ratio　comparing　with　that　of　the　plane　configuration.