This paper proposes a digital watermarking algorithm for remote sensing image based on DFT and watermarking segmentation. At first, it normalizes the host remote sensing image and determines an invariant centroid, then selects a square area around the invariant centroid for watermark embedding. Next, it generates a pseudo-random sequence as digital watermarking, and divides it into two parts. And finally it applies DFT to the selected region and embeds watermark into DFT phase and amplitude components of the selected square area of the host remote sensing image. Experiments have shown the algorithm's good robustness against JPEG compression, filtering, noise attacking, and it is also robust against geometric attacks as rotation, scaling, moving etc.