In view of the incompleteness of the current research on the evaluation of book influence, this paper explores and analyses the motivation of books being cited in the citation literature from the perspective of citation content. Firstly, based on the existing research, three classification criteria of citation motivation are summarized: use, comparison and background citation. Then, the citation content information of Chinese books in the citation literature of five disciplines was obtained, and the motivation label of the citation was marked. Finally, the distribution of book cited motivation and its relationship with citation location and length was analyzed. Empirical analysis shows that the proportion of "use" in book-citing motivation is relatively large. At the same time, there is a significant correlation between citation motivation and citation location, but no significant correlation with citation length. In addition, there are differences in the motives of citation of books in different disciplines.