Abstract: Traditionally, requirements analysis focuses on functions of target software system, and the analysis result is a complete, consistent, and nonambiguous software requirements specification（SRS）. With the research on software architecture and architecture based software production, analysis should also move its eyes from function centered view to structure centered view. Here proposed is a new analysis and modeling approach: agent oriented analysis （AOA）. AOA searches for a solution strategy for a families of problems rather than a special SRS. The result of AOA is an abstract information processing model: requirements architecture model. It is more and reuseful than SRS.It consists of an entity structure diagram, which defines static interaction structure of agents and objects, agent statecharts, which describe agents’ dynamic behavior pattern, and constraints.