To better support computer integrated abnormal situation management (ASM), a multiagent system architecture is proposed within which user and functional agents cooperate based on a collaboration mechanism. Each agent participating in the collaboration is composed of a local module and a collaboration module. Different types of collaboration are systematically analyzed. In particular, interactions among functional agents are represented by an ASM activity diagram and an extended signed digraph (SDG). A prototype operation support system for the simulated Tennessee Eastman process is used to illustrate the application of the framework and the collaboration mechanism.