This study proposed an analytic framework forcoding students’ dialogic argumentation and investigated the characteristics ofthe small-group argumentation pattern observed in modeling-based learning. Theparticipants were 122 second grade high school students in South Korea dividedinto an experimental and a comparison group. Modeling-based learning wasapplied to the experimental group in a topic of apparent motion of Mars on theother hand, explanation-based classes led by a teacher were provided to thecomparison group with the same topic. Students created a paper model of Marsretrograde motion and learned through small-group discussion about theastronomical phenomena which is represented by the created model and the reasonthat caused these phenomena. The analytic framework for coding students’argumentation in the modeling-based learning was composed into eight componentsand three categories including model-related statement, claim and reasoning.The results showed that a variety of model exploration is essential for usefulargumentation which includes the reasoning added with the claims. Byinvestigating the time sequential pattern of the argumentation, a process ofargumentation frequently cross all three categories was revealed as aneffective pattern in modeling-based learning. Additionally, the results ofcomparing the concepts of apparent motion of Mars in the experimental group andcomparison group, the ratio of students with correct concepts of theexperimental group was higher than those of the comparison group. Theimplication of these finding for modeling-based learning environment,productive modeling discourse are discussed.