A new digital watermark technique based on digital holography and discrete wavelet transform is presented.Firstly,the secret image is transformed into a digital hologram image by the means of discrete Fresnel diffraction.By one level wavelet transform,the host image can be presented by one low frequency approximation and three high frequency details.Lastly,the digital hologram image is embedded into the large wavelet coefficients.The experimental results show that the method is robust to the attack of the JPEG lossy compression,cropping and average filter.