A watermarking algorithm for image authentication based on statistical model and direction wavelet was proposed. The image directional flow was constructed by using directional wavelet, and it could depict the characteristic of the image. By applying noise visibility function, the noise visibility intensity was structured. The blocks of image, which contain more texture information,were selected to hide the image directional flow. The image was authenticated by comparing the hiding information and the image directional flow. This algorithm can well resist the JPEG compression and noise attacks, and it guarantees the quality of the sight. It is a blind detection algorithm, and this algorithm has high concealment performance and security.