Favored by developed countries and frequently resorted to by developing countries, anti-dumping is being expanded. Though various explanations are made by different literatures to this situation, the paper, based on the route in which anti-dumping is functioning, gives a try to trace from the current use of anti-dumping to those features that theoretically explain why anti-dumping is expanding.It finds that anti-dumping currently can not only survive but also be largely demanded, which is a somewhat wider perspective. In this paper, the economic theory of the occurrence of dumping, the influence of dumping and the trade protecting effect of anti-dumping, the legal aspect of anti-dumping as well as the political considerations undertaken during the process of making and implementing anti-dumping rules are discussed.