Abstract: People tend to form an internal model of systems and how they work. An accurate mental model helps promote user experience and performance. As a result, interface designs that are based on a users mental model have been discussed frequently. However, the concept of a mental model has varying interpretations and is considered difficult to operationalize. Against this background, we propose a framework that demonstrates the structure of a mental model and the role it plays in human-computer interactions (HCI). Accordingly, a method is proposd for interface design. This method is supported by recent cognitive psychology theory and is practical for engineering projects.