The present invention discloses a raster map copyright protection method based on a bacterial foraging algorithm (BFA) and a least significant bit (LSB). The method comprises: carrying out edge detection on the raster map by using the sobel operator, and extracting map edge data; dividing the edge image into a plurality of blocks according to the number of bits of watermark information; using the BFA algorithm to optimize the edge points in each block, and extracting optimal watermark embedding points until the number of extracted points is equal to the number of bits of the watermark information; and according to the position of the extracted points, embedding the watermark information into the corresponding pixel of the original raster map for each block by using the LSB algorithm. According to the method disclosed by the present invention, the generated raster map digital watermark can better resist the noise attack, the filtering attack and the geometric attack, has good concealment, and can effectively protect the raster map copyright.