In multi-agent system, the Requirement/Service is a cooperation way that is simple, efficient, and wildly applied. Under the framework of Situation Calculus, the agents? belief and intention are formalized, and some new communication actions are introduced into the earlier ConGolog. Consequently, we propose a Requirement/Service cooperative model and semantics for multi-agent System based on the extended ConGolog. What?s more, in terms of the model and semantics, we specify a case of the multi-agent system in the dynamic and incompletely known environment for achieving the cooperation based on reason about action.