Liu Yuan has been always neglected by the academia. In recent years, although the number of the research of it was growing, the results were still not satisfactory. Therefore, it was decided that the title of the current study involved Liu Yuan. In addition, Liu Yuan’s learning was in the Song learning system primarily and the Four Books were the core of it. For those reasons, his learning of the Four Books was decided to be the scope of the current study. And it was expected that the current study could breakthrough based on the previous studies of the academia.