Because of the community difference of Internet user, the new media can spend the most economgic advertising expenses to contact with target customer. But according to the IAB¡]Internet Advertising Bureau¡^report, 72% IA (Internet advertising) revenue was hold by the top ten America web site, the twenty-five and fifty gain 84% and 87% I.A revenue. The inadequate resources may cause the big web site become biger and the small web site die in the Internet, over a long period of time, it will affect the development of new media of Internet. The apperence of the Ad network solve the inadequate resources of I.A. The Ad network intergrated different content and classification web sites make the traffic close to the portal site increase the choices of advertiser/agent media selection. But as a result of unripe I.A market, the Ad networks provided different service, charge standard, the type of advertising deliver, and statistic forms have made advertiser/agent perplexeed. The objective of this research is to explore the criteria for advertiser/agent select the Ad network, and the satisfaction of the Ad network, then provides a consist principle to improve the Ad networks. The research uses media plan, the characteristi of I.A, the characteristi of Ad network four dimension to establish the questionnare, through the interview with Ad networks to modify the questionnare. Send the questionnares to advertiser/agent who ever spent I.A buget in Ad network. The research found that advertising/agent select the Ad network emphasize on the characterstic of Ad network and the personnel of advertising service. Through the factor analysis, the criteria of advertising/agent for Ad network selection can descripe as personnel service factor, the characterstic of Ad network factor, additional service factor, advertising design factor, marketing effect factor general web site attribute factor, advertising price and cost factor, the reputation of Ad network factor. In the aspect of satisfaction of the Ad network, advertising/agent had high satisfaction on providing on-line form monitor, analysis and the attitude and cordial of service personnel. Through the factor analysis, the satisfaction can divide to five index¡Xservice personnel, adstional service, marketing effect, the function of advertising monitor and analysis, and advertising effect. The research also found that the five index had poi tive correlation with the whole satisfaction, the whole satisfaction had positive corrlation with repurchase willingness and recommendation willingness.