Current online auction modes are all non real-time and have many defects. They are centered on auctioneers, forming star shaped information communication mode among auctioneers and bidders, and are actually the computerization of traditional auction mode. The power of Internet has not been fully utilized. In order to solve these problems, a real-time online auction mode is put forward. In this mode, bidders and auctioneers have peer-to-peer status, forming netlike information communication mode between two sides. The characteristics of real-time online auction are analyzed. The application of Multicast technology in real-time online auction and how to lighten the burden of bidders and auctioneers by intelligent Agent technology are elaborated. Finally, the application effect of real-time online auction is verified through an experimental system.