The minimal important difference (MID) plays a critical role in evaluating the clinical significance of health outcomes and reflecting patient values. This article systematically reviews the conceptual evolution of MID, its core functions in interpreting patient-reported outcomes and the GRADE evidence framework, as well as common methods for its estimation. Furthermore, it examines the current application of MID in the efficacy evaluation of traditional Chinese medicine (TCM). Nevertheless, this field still faces several challenges, including methodological heterogeneity, insufficient reporting transparency, and limited application in binary endpoints and TCM-related clinical practice guidelines. Future efforts should focus on promoting the standardization and normalization of MID determination methods, and strengthening its integration into the development of TCM clinical practice guidelines, so as to establish a more scientific and patient-centered paradigm for outcome evaluation.