The double filtering system based on single crystal acousto-optic tunable filter (AOTF) in order to improve spectral resolution and reduce side lobe is designed and demonstrated. The effects of single filtering and double filtering on AOTF performance are analyzed. Furthermore, the proposed double filtering technology has the characteristics of high speed, strong stability, flexible tuning, narrow bandwidth and multi-wavelength selection. In this experiment, the spectral bandwidth, side lobe and diffraction efficiency of single filtering and single crystal double filtering in visible range are measured. A double optical wedge compensator is set up at the exit of the double filtering experiment system to compensate the diffracted light drift caused by chromatic aberration. In conclusion, the experimental method of double filtering based on single crystal of tellurium dioxide is better than that of single filtering in spectral resolution and side lobe suppression.