This paper explores the political behavior process in information system implementation process. The organizational politics is the critical success/failure factor in the IS implementation process. We expect to understand, in different organizational contexts, what kind of political behavior will occur? What will be the events and processes of these political behaviors? Who's idea? At what time? In what setting? What will be the interaction among these dimensions? How will these political behaviors affect IS outcome and organization? This study will explain political behavior in IS implementation process from different interpretations and perspectives. This study relies on qualitative data collected from two cases--manufacturer Theta and government enterprise Delta--in the forms of interviews, documented data, archival data, and observation over eight month. The data are interpreted through five internally coherent theoretical perspectives: personal perspective, strategic contingency theory, conflict theory, social exchange theory, and structuration theory. Contributions include the following. In practice, we group 35 kind of political behavior into four types: aggression, defense, strengthen, withdrawal. Besides the adverse effects, some kinds of political behavior can lead to the success of the project. The detailed descriptions we use to describe the political behavior process in IS implementation process can help in similar cases to show how to reduce or prevent any negative consequences. Academically, we conduct contextual and process theory analyses of these processes, and use five theoretical perspectives to interpret these phenomena.