1. A method for dynamic two-way auction, applicable for auctioning participating goods, comprising: (1) setting, by a server. The descriptive information, possible search conditions and the relations which associate each search condition with the descriptive information of all participating goods are set up and stored on the server side. (2) sending, by a buyer terminal and/or a seller terminal, a search request which includes a search condition to the server; (3) parsing, by the server, the search request to obtain the search condition, determining whether a definition of a relation which associates the search condition with the descriptive information has been recorded, and performing step (4) if the relation has not been recorded; (4) defining, by the server, a relation which associates the search condition with the descriptive information of some participating goods.