This paper aims at extracting the boundary line of simple graphics.We select black and white pattern as the breakthrough point and analyze the data of coordinates point outline feature comprehensively. According to the principle of establishing the Bessel curve, based on the model, we build a graph boundary line of Bessel curve extraction, graphic boundary line extraction correction and simple color graphic boundary line extraction etc. Using Excel to process the data, using Photoshop, Matlab and other graphics software to extract the boundary lines, using Opencv to test the fitness of the lines. Finally, we compared the results to the actual and found that the vector edge line pattern close to the reality of pattern to a large extend.