Thispaper presents a goal based modeling methodfor agent-oriented software system. In modeling research for agent-oriented software, problems often emerged in that the properties of agent system were not efficiently reflected in the developmentphase (analysis, design, etc.), because the techniques based on other software paradigm are adopted to develop agent-oriented software. The result of analysis differs depending on which paradigm is used. Agent is goal-oriented, which necessitates a shgt in paradigm. Therefore, the modeling method for agent system should startfrom the concept ofgoal. Keywords Agent Modeling,RequirementAnalysis and specification, Agent Oriented Software Engineering (AOSE), Goal Modeling,