Researchers have established that solid argumentation is essential for developing, establishing and communicating mathematical knowledge, which attracted substantial attention from researchers, but few have simultaneously investigated the argumentation performance of sixth-graders and their teacher's potential influence in Chinese rural classrooms. In this pilot study, 33 sixth graders in a Chinese rural class were examined, and the math teacher who had been teaching them for three years was interviewed. Findings related to the students' performance revealed the need to improve their argumentation competency, including using more diverse modes of arguments and argument representation as well as developing more advanced types of arguments (e.g., deductive argumentation). The interview finding with the math teacher indicated that the teacher's perception and knowledge might impact students? learning opportunities to conduct argumentation and, therefore, may influence students? argumentative performance. Implications and limitations of this study is discussed at the end.