With the rapid growth of telecommunication technologies, comes a brand new communication paradigm: mobile Internet. Although the usage of the mobile Internet has been expected to increase rapidly, the profits of mobile Internet services providers do not seem to meet their expectations. As a result, this may result from mobile Internet users' initial adoption behavior. The main objective of this study is applying the data mining technology to investigate the relationship between demographic compositions and consumers' adoption of mobile Internet. A decision tree classification rule technique is applied to discover a classification model based on the consumers' sex, occupation, age and innovativeness. Especially, the consumerinnovativeness is measured by the new technology ownership. An on-line survey was conducted in order to find more mobile Internet users. There are 409 valid samples returned, including 151 users and 258 nonusers. The interviewees can be divided into three categories: users, potential users, and nonusers (unwilling to use). According to the results, sex is the most important factor for consumers' adoption. 72% females with digital camera and PDA have already adopted the mobile Internet as far. To have more effective ways of marketing, providers have to make great efforts on these two devices for cross sale in the future.