With the development of wireless network, especially the advancement of sensor technology, more and more context information is captured. Contextawareness has been a key enabler for providing users with customized services in mobile commerce. The context-aware computing, in essence, is a process to support decision-making. A key capability of a proactive context-aware system is to infer the user?s needs by constantly capturing and interpreting his/her context. From the last century, researchers have done a lot of researches about context aware services, but most of the researches are targeted at specific services domain, not brought forward a uniform reasoning process.