This Research explores the Critical factors about the willingness of individual subscriber as well as the respective personal background and customer demand that affect the willingness to adopt the third Generation Mobile Communication Systems. Meanwhile, an analysis is conducted on the Critical factors about the willingness of adoption and the influence of customer demand that affect the willingness in adoption. Based on the Theory of Reasoned Action (TRA), Theory of Planned Behavior (TPB), Innovation Diffusion Theory (IDT) and taking Technology Acceptance Module (TAM), additionally, making an investigation into the actual market status of application in Mobile Communication in Taiwan, the author is building up a structural model for the willingness of individual consumers to adopt the third Generation (3G) Mobile Communication Systems. Through the investigation from practical verification, this report is aiming at offering the 3G Industry and related Telecom Corporations and Operators in the field some referential information when establishing their marketing strategies, and on top of that, having a better understanding of the habitual practice and demand of consumers.