Digital watermarking technology is applied on multimedia data such as images, audio and video etc., for copyright protection and temper proofing. Vector type images are commonly employed in cartography or geographical information system, and their copyright or ownership must be protected. Previous works on digital watermarking of vector maps adopted the informed or non-blind method, which needs the original maps for watermark detection. In this paper, we propose a novel and blind watermarking approach, which firstly subdivides the map into mesh segments, and then embed the watermark in each segment. In the detection step, either map segmentation or watermark detection doesn?t need the original map. Simulation results show that the proposed approach also resists to cropping and noise attacks.