Based on mathematical morphology of digital image processing technology, an automatic recognition algorithm of gust fronts is devised. Based on the narrowband shape, velocity convergence, and moving rapidly of gust front, three parameters (difference between reflectivity factors of two adjacent times, velocity shear, and velocity gradient) can be gained. Taking into account of the three parameters, a 2D characteristic quantity field can be obtained. Applying binaryzation, dilation, corrosion, thinning, cutting, and conjunction, a curve corresponds to the skeleton of a gust front is shown as results. To evaluate the algorithm, the dataset of gust fronts (53 volumes) are applied. The results show that the algorithm recognized 39 cases correctly, and meanwhile, 3 cases are recognized falsely, and 11 are missing recognition.