The purpose of this study is to examine the analysis of discourse in problem-based learning environment at different levels of education (e.g. grade level 6-9). This proposed study will be empirical study that examines the results longitudinally based on using different tools for measurement. The data will be collected from different sources that are video tape, class observation, fieldnotes, and teachers' interviews. From the above reviewed articles, I found a lack of discourse analysis in constructivist-oriented problem-based learning environment. Moreover, this study will intend to know about level of understanding and level of critical thinking which correlate with different types of discourse. This propose study's hypothesis that PBL is a form of active learning environment which intends to involve students in search of knowledge-based educational discussion and enhance students critical thinking as long as they continously interact with the environment that influence their learning. PBL also develop logical reasoning by course of periods of years in education. Furthermore, this study also recognizes teachers' role as a facilitator and provide instant feedback on students' performance in PBL environment. Magoon (1977) argued that "educational psychology researchers must turn their attention to what the students and teacher do jointly to construct academic content and classroom culture for a course of study" (as cited in Allus,2010, p. 1). In order to understand kinds of talks in educational learning environment, I will used a theoretical framework of Mercer (1995, as cited in Allus, 2010) on various talks. However, I will also include Mezirow's (1997, as cited in Lim and Angelique, 2011) four level of reflective thinking as a predictor of critical thinking in learning process in PBL environment.