A detection and tracking scheme of a dynamic contour based on image fusion is proposed. In the scheme, an image fusion based on a wavelet transform is applied, and for the hierarchical fused images, a novel multiresolution dynamic contour is applied. This scheme has three advantages. First, it not only retains the advantage of a monoresolution dynamic contour, but also decreases the strict requirement to an initial contour. Second, the relation formulas for a dynamic contour and the allowed target velocity in different resolutions are derived. According to these formulas, the allowed maximum target velocity is calculated quantitatively in monoresolution and multiresolution cases, proving that this scheme can track a fast target. Finally, more accurate image information of the fused image is applied in this scheme, which increases the detection and tracking accuracy of a dynamic contour.