To understand information system (IS) or information technology (IT), gender differences are the potentially critical issues. Getting more insights into the differences of gender, case study was applied to explore them in information system usage and then compare the difference between man and woman’s System Influence Diagram (SID). Some findings were explored in this study. First, woman put more emphasis on function of information system, yet man focus on management function in organizations. Second, man thought that user habit and perception interacted with information system design. But user habit was just influenced by system design directly in woman’s SID. Third, there was a feedback loop in woman’s SID associated with management function but no feedback loop in man’s SID.