This study aims to discuss some problems and tasks for developing assessment tool of basic reading ability by grade. We start from a few questions that is what is ‘basic’, how do we decide, and why. To answer this questions and develop assessment tool, first of all, we need to understand achievement level in reading. After setting achievement levels by grade, it is effective and easy to define basic reading ability by grade. So we research into reading process and reading ability development to increase understanding achievement levels in reading. The achievement levels setting process carefully designed, implemented, and evaluated with great attention to detail and technical precision. The process of developing achievement levels involves the judgement informed. well-qualified researchers and plenty-experienced teachers from throughout the nation and territory. At this aspect, lots of research executed by our national institution has some problem. For example, the ability of emotional reading or transforming contents, it is important for mother tongue reader, is not considered importantly. We discuss several problems that should be solved to develop achievement level and assessment tool, like this problem. We hope this study is a step to develop achievement level and assessment tool of reading and a stimulus to encourage lots of researches through various methods