Classroom dialogue is commonly used in teaching and learning, and viewed as in terms of helping students to think critically and understand knowledge better. Thus, educators and scholars call on active participation in classroom dialogue. However, students in mainland China are traditionally viewed as less talkative in class. In this study, I aimed to investigate how Chinese students in secondary school normally participate in classroom dialogue. I designed an instrument for measuring students' participation, and my research yielded initial evidence for its reliability and validity. The findings indicated that most students generally talked less and the teachers took the lead in initiating dialogue. Accuracy was used as the main criterion for evaluating whether students made a good contribution in class. A positive change was that students developed their reasoning through participating in dialogue.