Embodiments of the invention disclose a contour etching method and device. In the method, a contour mask is computed according to the dimension parameters of contour segments, a contour mask algorithm and an aperture radius, wherein the contour mask has the same compensation etching amount at each contour segment, in this case, even if the etching amount obtained at a corner is identical to the etching amount obtained by other parts of the contour, so that if the corner in a to-be-etched pattern is a round fillet, the corner is still the round fillet after etching and cannot become a sharp corner. Furthermore, the method carries out pattern Boolean operation on each contour segment and the contour mask and combines the contour segments included in an overlapping region in the to-be-etched pattern subjected to etching compensation, so that the extra contour segments can be eliminated. Through the contour etching method disclosed by the embodiments of the invention, an etching result is the same as an excepted etching result, so that a problem that the etching result is different from the excepted etching result in the prior art is solved.