A design method for multi-agent system is presented, named DPMAS. DPMAS uses agent UML, an extension of the UML in Object Oriented domain, as its modeling language. It provides a group of graphs to help designers in modeling multi-agent systems. Many agent specific concepts and denotations are introduced in these graphs. DPMAS suggests a design process that covers requirement specification, task specification, agent specification and deployment description. A tool called AUMP has been developed to aid designers in drawing graphs used in DPMAS. AUMP is the design platform of the well known MAGE 2 agent environments.