In　order　to　obtain　wideband　of　Acousto-Optic　(AO)　deflector,　curves　of　the　abaxial　angle　vs　ultrasonic　wave　frequency　under　different　conditions　are　systematically　studied.　By　solving　the　Dixon　equation　of　anisotropic　Acousto-Optic　diffraction　in　LN　crystal,　wide-band　operating　mode　of　AO　deflector　is　determined.　The　design　parameters　show　that　the　band-wide　of　AO　deflector　can　be　efficiently　widened　by　selecting　the　appropriate　direction　of　incident　light　and　proper　abaxial　angle　of　the　ultrasonic　waves.