Abstract: Compared with the traditional spectral imaging instruments, an acousto-optic tunable filter is a new type of imaging spectrometer, which can obtain target polarization spectrometer and two-dimensional spatial information. However, AOTF can only receive the beam with angle less than 5～6 in the practical application. Because of the limited receiving angle, AOTF spectral imager optical system can not achieve the large aperture and large field of view at the same time. We developed the AOTF imaging spectrometer field of view to meet the requirements of 128128 pixels and the TeO2 crystal size of 10mm10mm. Based on the features of the acousto-optic tunable filter imaging spectrometer optical system, an optimal system design was determined, the aperture stop was placed in the crystal, aperture stop size was limited by TeO2 crystal size, and the system field of view was determined by the crystal. The energy utilization ratio is improved and the signal to noise ratio of the image is increased.