Requirements engineering and software architecting are two key activities in software life cycle. Researchers have paid much attention to mapping and transformation from requirements to software architecture, but there's still lack of effective solutions. In this paper, the inadequacy of traditional mapping approaches (such as approaches in structured method and OO method) for this challenge is analyzed, and further a feature-oriented mapping approach is introduced. The rationale, process and guidelines for this approach are specified, and the approach is illustrated by an example of bank account and transaction (BAT) system.