Image edge detection has been widely used in practical applications, but the details of images are lost in the detection result. To solve the problem, a new image edge detection algorithm was proposed. Firstly, the two-dimensional binary wavelet transform was used to pre-process the image. Then, the edge points of the image were detected by using a new adaptive dual-threshold algorithm. Finally, an improved mathematical morphological gradient detection algorithm was used to further detect the edge information of the image. The simulation results show that: 1) The new algorithm can detect more edge information of the image, and the extracted edge of the image is more clear and delicate;and 2) Compared with single morphological algorithms, this algorithm greatly decreases the mean-square error value of the image and increases the peak signal-to-noise ratio by 2. 3 dB.