As an efficient approach to illustrate ambiguous knowledge, the linguistic hedge sets express decision makers' interpretations in line with linguistic habits. Compared with other linguistic terms, the linguistic hedge sets aim to modify the member function, so they are much more valid and objective in expressing experts' decision-making information. Thus, it is necessary to study the linguistic hedge sets. In this paper, we present the retrospection of the research of linguistic hedge sets. we first review the research background of the linguistic hedge sets. Then, we recall the operational laws, semantic quantification, fuzzy logic, and classifiers of linguistic hedge sets. At the same time, we present some applications of the linguistic hedge sets in sentiment analysis and engineering risk management. Finally, we look forward to the future research of linguistic hedge sets.