The purpose of this study was to investigate differences on problem solving process with problem structure in learning environment. To achieve this, the study compared functional message content and group interaction patterns in F2F and Web-based groups in terms of problem solving activities while solving ill-structured problems. For this study, 24 students' data were collected from K university freshmen in Seoul. Event sequential analysis was used to measure messages frequency and interaction patterns between threaded messages from F2F and Web-based. It was found that there were in ill-structured problems. there were differences message content and group interaction patterns between F2F and Web-based in ill-structured problems. The quantity of messages in Web-based than in F2F conversation was smaller but reflected more on their critical thinking and ideas in reaching their decisions for problem-solving. It was also found that participants suggested messages paratactically with criteria development(CD) and solution development(SD) in Web-based. The other side, students discussed as suggesting their additional one with other person's opinions for one solution development in F2F. In additional, Participants made one solution development rapidly through frequent phases of OO and solution approval(SA) in F2F environment while solving problems. In this study, Web-based environment enabled learners to participate critical thinking activities interactively in group collaborative learning process. There was differences of problem-solving process in collaborative learning environment. In additional, there are clearly advantages and disadvantages of F2F and Web-based for supporting group problem solving for ill-structured problems. From this results, It was discussed the implication for designing the collaborative learning environment.