Crimped conductor is primarily used in constructing overhead lines, and its edge distance is crucial for ensuring safe operation and a long service life of the line. To address the limitations of poor reliability and low efficiency in traditional manual measurement, a novel method based on image processing was proposed. Firstly, the measured area was automatically cropped based on the cumulative grayscale mutation points of the image and then median filtered. Subsequently, a binary image with continuous edges was obtained based on the improved Otsu thresholding method. Then, the edges were located twice using morphological processing and the Gaussian curve fitting method, respectively, and sub-pixel level edge points were obtained. Finally, the upper and lower edge points were fitted using the least-squares fitting method based on RANSAC to achieve the measurement of crimped edge distance. The simulation test confirmed that the measurement algorithm produces better results after 10 iterations of RANSAC fitting, with a measurement error of less than 0.1 pixels. The actual wire measurement test results demonstrated that the improved Otsu algorithm is adaptable to changes in light intensity. Furthermore, when compared to manual measurement, the image measurement method has a maximum relative deviation of only 1.82%, a 60% increase in repeatable standard deviation, and consumes only 1/10 of the time. The efficient and reliable measurement of crimping edge distance is realized.