Purpose/Significance To explore the identification method of interdisciplinary topic evolution path in medical informatics, so as to provide references for the interdisciplinary research layout and scientific research management in this field. Method/Process Firstly, global and staged topics are identified from medical informatics literature using BERTopic and large language models (LLM). Secondly, interdisciplinary topics are determined based on a two-dimensional analysis framework integrating topic influence and disciplinary diversity. Finally, the evolution paths of these interdisciplinary topics are analyzed. Result/Conclusion An analysis method based on Topic-LLM is proposed, and it is found that the disciplinary diversity and topic influence of interdisciplinary topics in medical informatics exhibit a steady growth trend.