China’s ongoing new curriculum reform has prompted extensive changes in student academic assessment. Therefore, assessment literacy is now recognized as a central component of professional standards for teachers. The enhancement of assessment literacy among primary and secondary school teachers represents a significant aspect of their professional development. In addition, it represents a critical element influencing the reform and advancement of basic education. Utilizing a self-developed assessment tool, this study determined that primary and secondary school teachers in China’s X province possess assessment literacy levels exceeding the average. However, significant differences exist based on school location, teaching grade level, professional background, years of experience, professional title, and class size. Notwithstanding the overall positive findings, several challenges remain, including deficiencies in assessment knowledge and differences in assessment practices between urban and rural teachers. Besides, issues of insufficient overall assessment literacy and comparatively lower levels among novice teachers require attention. Addressing these identified issues through research offers valuable theoretical grounding for the adjustment, development, and execution of relevant policies.