Considering the benefit of applying e-learning for teaching and learning, such as sharing ideas, seeking input, and giving feedback and clarification, one approach is an online discussion forum that provides learners with a wide opportunity to exchange and work collaboratively. In fact, some researchers have also advocated using collaborative learning activities. Considering the benefits of using online discussion forums and collaborative learning, especially the online discussion forum, this study focuses on preservice teachers using online discussion forums in General English. The aims were to analyze the knowledge construction that can occur while having a discussion and it was done by examining transcripts with the Interactive Analysis Model. In addition, this study also analyzed learners' collaborative behavior working in groups. The results revealed that most of the exchanges occurred in Phase 1: "Sharing and comparing information," i.e., 39% for Topic 1: "Favorite places," and 64% for Topic 2: "Traveling plan," and the fewest exchanges were in Phase 5 ("Application of newly constructed knowledge") that had 6% for both Topic 1 and Topic 2. To conclude, this study describes various knowledge construction and collaborative behavior phases. Further research in the online learning environment is needed to identify preservice teachers' learning needs and obstacles in cognitive and social-economic issues.