Artificial intelligence (AI) teaching is becoming an increasingly popular topic among educators and researchers, but the research on AI curriculum for K-12 classrooms was under-explored. Currently, most studies examine the curriculum content of the United States and the European countries. However, there has been limited research on AI learning design and activities in the Asia-Pacific region. This meta-review examined 14 research papers on AI curriculum for K-12 classrooms that were taken in the Asia-Pacific region from 2018 to 2021 by identifying the content knowledge, tools, platforms, activities, theories and models, assessment methods, and learning outcomes of the selected studies. The results indicated that AI curricula can develop students' AI knowledge and skills, learning attitudes, and interests. Furthermore, the research on AI education was conducted using both qualitative and quantitative methods which are useful for future educators and researchers to understand how they assess students’ AI learning performance. We also derive a set of implications for innovative pedagogical designs in terms of educational standards, curriculum designs, formal/informal education, student learning outcomes, teacher professional development and learning progressions to recommend how governments, researchers and educators could build a widely-accepted and age-appropriate AI curriculum for all K-12 learners.