In this study, an effective method about image edge detection is proposed from the local energy. In the symmetrical region centered on one pixel, we compare the differences of the gray value between every pixel all around the region and the pixel in the center. And the local energy of the central pixel is the sum of all the difference squares. The local energy can be used to detect the image edge effectively, because the local energy of the edge point is bigger than the pixel in the smooth region. And edge point can be precisely found, according to the local energy function constructed in the study. The Baddeley Error Metric (BEM) method is used to evaluate the accuracy of the proposed method. The experimental results show that the proposed method is better.