Crystallization of chalcogenide glasses provides a new possibility to decoupling the trade-off between acousto-optic figure of merit (M2) and acoustic attenuation (α) properties of acousto-optic materials. In this work, 62.5GeS2-12.5Sb2S3-25CsCl chalcogenide glasses ceramics were prepared, and CsCl nanocrystals were precipitated and evidenced by using scanning electron microscopy and X-ray diffractometer. The precipitation of CsCl nanocrystals led to a 10 % decrease in M2 from 113.85 to 102.08 × 10−18 s3/g, but also to a substantial improvement in α, which decreased by 38 % from 3.28 to 2.03 dB/cm. The glass crystallization that together with a rearrangement of the glass network structure would result in the enhancement of network rigidity of the residual glass matrix, thus contributing to the reduction of acoustic attenuation.