This study examines how the beliefs of Chinese in-service teachers regarding knowledge and knowledge acquisition influence their instructional classroom practices in junior secondary schools directly or indirectly through their conceptions of teaching and learning. The results indicate that the factor of learning effort/process is highly valued by Chinese in-service teachers in their epistemological beliefs, and that the constructivist approach is the dominant conception on teaching and learning for junior secondary school teachers. In addition, the constructivist conception of teaching and learning is found to be positively related to three types of classroom instructional practices, whereas the traditional conception about teaching and learning is found to be only significantly and negatively linked to standard contemporary practices. (Contains 9 tables and 2 figures.)