The invention relates to a method of automatic extracting seal image from Chinese handwriting and drawing works, and the method comprises following steps: The L*a*b* component color analysis and the method of mapping the analysis results to the RGB color space are used to filter the non-red color information from the target image; The remained information of the image is de-noised; The non-seal information in the remained information of the image is eliminated using the geometrical region based secondary splitting and filtering method, the communication region based image filtering method andthe margin detection method; and the existing position corresponding relations between the rectangle L3 and the Chinese handwriting and drawing works are used for image splitting and extracting. The invention provides a method of accurate and automatic extracting all seal image information from a part of or the whole part of a digital image of Chinese handwriting and drawing works, so the invention establishes a foundation for realizing contents-based Chinese handwriting and drawing work image indexing system with the seal image as the key information. The invention can be widely used in the field of cultural relic digitalization.