Abstract: An approach for identifying symbols in scanned map based on mathematical morphology is proposed.First,preprocessing of scanned map is discussed,such as geometry processing,image background subtracting and contrast enhancing based on top-hat transform,thresholding etc..Then a bidirectional matching method based on mathematical morphological is used to identify symbols in the preprocessed scanned map.The experimental results indicate that the proposed method is more efficient and more reliable in identifying symbols in scanned map than the traditional template matching method;and the average correct accuracy of symbol identification is up to 90%.