As the mobile communication network evolves into third-generation technology (3G), the mobile office are still developing slowly. Therefore, this study is trying to identify the critical factors for high-tech and manufacturing employees in Taiwan to accept the mobile solution for office by using 3G technology and examine the causal relationships among variables. The reason we choose the high-tech and manufacturing industries is that they are the most important industries in Taiwan and dominate the growth of Taiwanese economic. Based on the Theory of Planned Behavior (TPB), exogenous variables such as perceived risk, compatibility ... and so on, are discovered. Some discussion, suggestion and future research direction are also provided.