Research Findings: This study employed multiple approaches to examine the stability of teacher–child interaction quality in Chinese preschools. Teacher–child interaction quality was measured using the Classroom Assessment Scoring System (CLASS) on five observational cycles within a school day. Several different metrics of stability were examined: (1) standard deviation; (2) correlation; (3) measurement invariance; (4) mean-level change, and (5) state–trait framework. Overall, results suggested that children in Chinese classrooms experienced the same facets of quality as measured by the CLASS as has been found in other countries. Furthermore, results indicated consistent quality levels of Emotional Support and Classroom Organization, and relatively inconsistent quality levels of Instructional Support within a school day. Practice or Policy: Building on previous work, this study contributed to the field by enhancing our understanding related to the dynamics of within-day variability of teacher-child interaction quality. Chinese teachers could benefit from evidence-based professional development guided by the CLASS framework. Tools such as the CLASS could be used to guide teachers to improve their instructional interactions in both quality level and stability.