Commentary is one of the core concepts in narratology and as the major device of narratorial/authorial intervention or intrusion, it is not only an integral element in constituting a complete narrative framework or process, but also embeds and communicates the narrator’s/author’s ideology, norms and values. Whether it is the narratological/rhetorical approach represented by Booth and Chatman, or the linguistic approach proposed by Labov and Fleischman, they all seek to explore the conceptual definition and typology of commentary or evaluation, and focus more on its functions in different forms of narrative. Despite the theoretical platform provided by these studies, there still exist some problems, for example, the inconsistent criteria in deciding the types, the unbalanced focus, and even the generic prejudice.