The downburst is the outburst of divergent flow on or near the ground induced by a strong convective downdraft. A single downburst affects a small area of several kilometers, and the downburst cluster can extend over several hundreds of kilometers resulting in many noncontinuous surface damaging gusts. Its enhancing mechanism may not be limited to the strong downdraft divergent outflow. This article reviews the definition of downburst, and dicusses downbursts under two different situations. One is the downburst induced by isolated storms and the other is the downbursts embedded in mesoscale convective systems, including the formation processes of downburst and warning technology of downburst based on Doppler weather radar. On the basis of the above review, the formation mechanism of downburst and the difficulties of warning are discussed, and the much-needed issues related to downburst are listed.