People make many decisions in their life, most of which may be made without much explicit deliberation. Mobile phone buying is normal behavior in our life, but which factors affect the purchase decision is still not clear. When people choose to buy a particular brand of phone, most make the decision based on a variety of reasons, including individual interest, the exterior, functions, impression of the brand, etc. However, what is the main reason affecting such choices? What are the impacts on the decision-making of the different specifications? In this study, we investigate these questions in depth.