The interactions between the task process and members' behavior take place through the match of members' ability and demands required by tasks and the enhancement of one's ability through learning in task process. To address how the interaction affects team effectiveness, a multi--agent model is put for- ward based on casual anaIyses of various factors involved in team's task process. The model is implemen- ted into Member--task Interaction based on Team Effectiveness Simulation System by Repast. J 3.1. Ex- perimental scenarios are designed...