Abstract: The concept of Mapping of Knowledge Domains and the CiteSpace(a information visualization tool) get a lot of attention quickly since they introduced in domestic academia, the relevant literature spring up like mushroom in a variety of domestic information science journals. But we find the knowledge visualization tool is "abused" and "misused" seriously by reading more than 500 papers that applied CiteSpace ,which shows that academic circles is lack of sufficient understanding of the methodology function of Mapping of Knowledge Domains. This article makes a deeper interpretation on CiteSpace from four aspects, design philosophy, theoretical basis, applying process and application function, which will benefit domestic scholars to deepen the understanding of the tool, and apply the tool more flexibly and effectively in scientific research.