In this paper, a robust image watermarking algorithm is proposed, which adopts the Hilbert scanning, and uses JND (just noticeable distortion) matrix based on HVS (human visual system) characteristics to mask the watermarking signal when embeds the watermark. And the strength of the watermark can be self adapting. Auto Rectification can also be added, which greatly improves the accuracy of watermark detection. Based on the description of the algorithm, experimental results and attack analysis are given. The experimental results show that this algorthm is transparent and robust.The detection results are faithful and the computational cost is low.