Based on Hyland’s (2005) interactional metadiscourse model and the identity construction category proposed by Sun (2015), this study attempts to make a comparative analysis on the characteristics of the frequencies of interactional metadiscourse between Chinese masters’ theses and international journal articles, as well as on the similarities and differences of author identity constructed with interactional metadiscourse. The findings are as follows: (1) from the frequencies of interactional metadiscourse, Chinese masters employ significantly fewer hedges, boosters, attitude markers, and self-mentions in their academic writing than international journal authors, while utilizing markedly more engagement markers. Regarding the subcategories of attitude markers, the two author groups possess notable differences in judgment markers, appreciation markers and affective markers, in which the significant difference in judgment markers is relatively low. The results suggest that the frequency of interactional metadiscourse utilized by Chinese masters in academic writing is inferior to that by international journal authors. (2) The identity categories constructed with interactional metadiscourse by the two author groups are in the descending order of researcher, interactor, and evaluator. Compared with international journal authors, significant differences are discovered in the identities of self-initiated interactor, other-initiated interactor, self-evaluator, other-evaluator, cautious originator, and confident researcher constructed by Chinese masters, whereas no difference is found in the careful advisor identity constructed by the two author groups. This study enriches the research of interactional metadiscourse from the perspective of identity construction, and the findings could provide references for improving students’ awareness of academic writing.