Previous survey showed that the ihportal sitelt would be the place where Internet users visit most often. In this study, we employed the TAM in studying the portal site, and identified antecedents including information content, customization, reliability and response, and security to perceive ease of use and perceived usefulness on portal site usage. In validating our research model, our data supported all the individual causal paths postulated by TAM. The results demonstrated the antecedents contributing to portal site usage and those affecting perceived usefulness and perceived ease of use. The importance of significant antecedents such as information content, customization as well as the reliability and response to portal site usage could provide the companies as a referential point for designing mechanisms and improving users' perceptions of the portal site. Based on the research findings, implications and limitations are discussed.