Obviously, higher speed and wider coverage of mobile broadband data transfer service have become the trend of the next generation of telecommunications technology, even though mobile broadband data transfer is not currently widespread in Taiwan. In actual fact, there are some previous studies that focus on the development trends or market potential forecasts of the telecommunications industry. However, most of the previous research conducted to estimate mobile internet market potential neither considered customer preferences nor environmental factors. Moreover, some also considered customer preferences in analyzing the development of mobile broadband without considering the environmental factors. In order to fully estimate future demand and provide implications for businesses and policy-makers, considering the consumers' preferences is very important in order to cope with the development of the telecommunications industry. Therefore, the objectives of this research are to analyze the development of the next generation of mobile telecommunications technology, and especially the diffusion situation for each different generational technology, i.e., 2G, 3G, Worldwide Interoperability for Microwave Access (WiMAX) and long-term evolution (LTE) in Taiwan. In order to make our research more conscientious and complete, we perform conjoint analysis to analyze the customers' preferences and scenario analysis to address the possible scenarios of the mobile telecommunications industry. Furthermore, we combine the results of customers' preferences and the elaborate specified scenarios, and then use the innovation diffusion model to forecast the market shares of 2G, 3G, WiMAX and LTE in Taiwan over the next 10 years.