This paper describes the architecture of an instructional planner in an intelligence tutoring system. A three-layer blackboard model is presented. In this model, each knowledge source can be designed independently. New knowledge can be added to the system without affecting the design of other knowledge sources. Therefore, the archi-tecture provides the possibility of capturing more intelligence in future. Included in this architecture are three knowledge sources namely, the domain knowledge, pedagogical knowledge and the knowledge of individual student. The architecture also reflects multiple flexible tutoring strategies in providing instruction for individual student.