The technology of this application relates to a flow characteristic extraction method and apparatus, and belongs to the field of network technologies. The method includes a network device that determines a burst parameter of a burst traffic segment of a received first packet flow, and determines a burst parameter of the first packet flow based on the burst parameter of the burst traffic segment of the first packet flow. The first packet flow is an elephant flow, the burst traffic segment indicates a burst degree of traffic within one period of time, the burst parameter of the burst traffic segment is a parameter used to describe the burst traffic segment, and the burst parameter of the first packet flow is a parameter used to describe at least one burst traffic segment included in the first packet flow.