Traditional Chinese medicine (TCM) syndrome differentiation, as the core of the traditional Chinese medical system, has played an indispensable role in guaranteeing the health of the Chinese nation for thousands of years. Recently, with the collaborative promotion of multiple departments, the TCM technology innovation capability of China has been continuously enhanced. The integration of TCM syndrome differentiation with artificial intelligence AI, big data, and other fields has made new progress. Engineering frontier methods and technologies have provided an effective route for breaking through the theoretical bottlenecks of TCM syndrome differentiation. Against the backdrop of the modernization and intelligent development of TCM diagnosis in the new era, this study summarizes the fundamental theories, basic processes, and key technical links of AI-assisted TCM syndrome differentiation. The key technical links include multimodal data fusion, symptom correlation analysis, syndrome quantification, syndrome reasoning, and large-scale TCM models. It also expounds on the research ideas and development status of each link and summarizes the challenges faced by AI-assisted TCM syndrome differentiation. For instance, publicly available data are insufficient and have a poor quality; syndrome differentiation models are inadequate, have poor universality, and lack interpretability and consistency; and the evaluation of syndrome differentiation model results is limited and lack credibility. Therefore, the following suggestions are proposed for reference: (1) strengthening data integration and quality control; (2) deeply integrating AI with TCM syndrome differentiation to enhance model interpretability; (3) developing large language models for the subdivisions of TCM; (4) strengthening the construction of intelligent TCM talent teams and encouraging cooperation among experts in multiple fields; and (5) improving international standards and regulations to strengthen international cooperation and exchanges. These efforts aim to provide references for the technological exploration and innovation of AI-assisted TCM diagnosis and treatment.