The digital watermark technique is proposed based on Fresnel hologram and Discrete Cosine Transform (DCT). The Fresnel hologram of the original watermark is gotten by use of digital holography technique. Then the hologram is embedded in the median-frequency coefficients in the DCT domain. The position of watermark and geometric parameters of optical system are adopted to retrieve the watermark without the original host image. The algorithm has high security and practical value. Numerical experiments show that the embedded watermark is robust to usual image manipulations,such as superposing noise,cropping,filtering and lossy compression. Therefore,there is an application prospect for the algorithm.