Abstract: The Fourier transform characteristics of off-axis hololens was discussed,which was made by using a dot light source and an inclined parallel light.The Fourier transform power spectrum of input object can be obtained when the input image is placed at the front or back of the hololens.The more small the size of input image is and long the focal length is,the more small the error is.The exact Fourier transform of the object can be obtained when it is placed at the front focal plane of the hololens.At the end of this paper,the optical experimental results are given.