Abstract: Based on the system design cooncept of acousto-optic tunable filter(AOTF) imaging spectrometer, optomechanical design for an acousto-optic tunable filter(AOTF) imaging spectrometer was presented. It consisted of three group optic lenses. The fore-optical system included objective and collimating lens and the imaging lens collected the +1 and -1 orthogonally polarized orders produced by the AOTF at the same time. The whole system is achromatized from 0.4～0.9 microns and imaging resolution is better than 32lp/mm when MTF reach 0.7.