In this paper, an olight incident acoustooptic tunable filter (AOTF) based on TeO2 crystal has been fabricated, and its beamsplitting principle is analysed theoretically. A series of common formulas of olight incident AOTF, such as ultrasonic pole angle, aperture angle and tuning relationship between light wavelength and frequency, are derived. The accuracy of these formulas is verified by actual measurement and analysis. The experimental results show that the olight incident AOTF can perform the spectral imaging analysis on the olight characteristics of the target, which makes up for the insufficiency that the elight incident AOTF can’t analyze the olight characteristics of the target.