Abstract:By using the marking and dimension tools of image measurement software, the measuring lines can be directly exported to CAD to realize reverse design. Because the shape error of wire-cut parts is 0.02mm, the alignment error is 0.01mm when the measuring cross line is aligned with the contour edge. At the same time, the measuring error is also 0.01mm as the point motion control precision of the software is 0.01mm. Through error mechanism analysis and measurement uncertainty evaluation, it is concluded that the actual measurement accuracy is ±0.018 mm when the image method is used to measure the wire-cut parts, which meets the requirement of the tolerance ±0.05mm setting of the parts, and provides theoretical guidance and practical verification for the image method in measuring the medium-size parts.