The purpose of this article is to address the role and status of policy discourse in policy change. Basically, policy change is assumed to be the interactive effects of three streams of force: deconstruction, construction and strengthened original structure. These three streams of force are expressed by policy actors through policy discourses during the policy making process. Hence, the approach of policy discourse is ＂a feasible way to observe and analyze the complexity of policy change.

Another focus of this paper is to construct four basic types of policy change: policy evolution, policy succession, policy termination and policy growth. Then we turn the direction of analysis to the definition of each type of policy change and the impact of different streams on each of them.

However, the analysis of policy discourse not only needs to focus on the content of discourse texts, it also needs to identify its embedded social structure, available texts, the position of discourser in policy networks, the policy itself and its contextual evolution. These five factors will determine discourse ownership and leading status and the magnitude of discourse acceptance. Moreover, they lead the possibilities, direction and implication of policy change.