Recently, organizations intend to adopt new information technology for acquiring relative advantages in competitive business environment. Especially, many companies have paid attention to web-based electronic commerce. But research in this area has largely been performed to the operational and technical aspects of web site. Also the World Wide Web(web) has become one of the most widely used information technologies, but research indicates that there are many firm that are still considering whether to establish a web presence. This study examines factors influencing adoption of corporate web site over time. To examine why companies adopt web site, this study regards web site as an innovation and finds out these reason through Innovation Diffusion Theory. Independent variables of this research are composed of innovation characteristics, organizational characteristics and environmental characteristics. By the result of logistic regression analysis, we find that there are significant differences between early adopters and late adopters of web site for three adoption factors : top management support, organization size, environmental uncertainty. These findings confirm the theoretical frame for adoption of corporate web site. Also this study will provide good guidelines to the companies and the vendors in shaping the strategies of IT adoption and IT diffusion respectively.