In order for classroom and online discussion to be meaningful and fruitful, this study purports to develop a model about how to design the preparatory instructional system and its actionable instructional strategies that has to be preceded main discussion activities. On the basis of Schreier’s qualitative content analysis(2012) and the selection criteria for instructional strategies offered by Reigeluth and Frick(1999), this study analyzed scrupulously the related major theories and research results. In this respect, the major reasons why online and classroom discussion fail or succeed, were investigated. The failures are unrealistic expectations for the discussion by teachers, lack of ground rules, insufficiency of teacher modelling, unprepared students. The successes would be described in terms of establishing the learning environment, discussion learning culture respecting the ground rules, pre-training for discussion strategies, proactive treatment supposed to prohibit the crippled implementation. Based on the factors investigation, this research devised a design framework for the preparatory instructional system. Their major elements are as follows: 1) establishment of the learning environments, 2) culturalizing the ground rules, 3) pre-training for discussion strategies, 4) Settlement of the three elements by teacher’s interventions. In addition, the practical instructional strategies for each element are provided for teachers to become a better instructional designer and facilitator for online and classroom discussion. Moreover, limitations and constraints of this study and the related further research are suggested in detail.