To adapt to the further requirement of measurement accuracy of slight photo electric signal in the field of modern photoelectric detection technology, high-precision measurement method of diffraction efficiency of Acousto-Optic Tunable Filter (AOTF) was proposed and verified. Light path switchable devices was used to achieve cross-reference detection, reducing the effect of light source instability, non-uniform response of the detector and photoelectric-jamming, which improved the accuracy of measurement effectively. Firstly, the principle of high-precision measurement of diffraction efficiency of AOTF based on double-optical-path and cross-references was introduced concretely in this paper. Experiments were performed to testify the accuracy of this method. Experimental results indicate that the diffraction efficiency measurement accuracy is improved 50 percent averagely by using cross-references approach. The proposed method has a significance to reduce the influence of source instability and response difference in detectors, and improve high-precision measuring. Finally, the range of application and referential meaning of this method were also discussed and analyzed.