Abstract: According to the multi-scale propagation characteristic of image edge and noise as well as principle of edge detection using wavelet transforman，an algorithm based on cubic B-spline wavelet and directional derivative is presented.The algorithm takes not only edge direction of an image，but also symmetry and linear phase feature of the wavelet base into account，so well resolves the contradiction between the detection precision and the noise suppression ability.Computer simulation results show that this algorithm is superior to traditional edge detection algorithms with both precise image edge detection and effective noise restraining.