In this paper, we propose a new scheme for observing and controlling behavior of the QoS(Quality of Service)- aware agent organization, which provides a flexible QoS control of multimedia service components. In particular we propose two models, i.e., Flexible Distributed System (FDS) Model and its Behavioral Characteristics Model (BCM) in this paper. By using these two models, a multiagent system with the flexible QoS control capability that can deal with changes of system?s operational situations to maintain the required QoS as well as its behavioral characteristics.