Abstract: As the small targets in the eletro-optical image are composed of tiny pixels, the detection of small targets can be regarded as the singular value detection of the target signal, and the wavelet-based multi-scale analysis is an important detection method of signal singular value. This paper analyzed the principle of small target detection using the existing wavelet-based multi-scale analysis method, and its use in the estimation of the modulus maxima value line is difficult and target location accuracy is not good. Based on the symmetry of wavelet function and small target signal, a method is presented to detect the small target in electro-optical image directly based on the wavelet analysis over two different scales. Finally, experiments proved that the method can improve the detection speed and location accuracy effectively.