Abstract: 【Purpose/significance】 Intangible cultural heritage documentaries display excellent traditional culture in a vivid and au⁃ thentic form, analyze the content of online comment after watching the documentary, explore the potential audience demand, and pro⁃ vide reference for the research on the audience behavior of intangible cultural heritage documentaries.【 Method/process】 Taking the intangible cultural heritage documentary "Masters in Forbidden City" as the research object, this study firstly collect comments from bilibili website and preprocess the comment data, then identify and extract causal event pairs in the comments based on the causal rule template, then invoke the LDA model for theme clustering, and summarize the clustering results based on the use and satisfaction theory. Finally, the Gephi tool is used to visualize the event logic graph. 【Result/conclusion】 The results show that the audience mainly have four needs, including knowledge acquisition, aesthetic acceptance, emotional resonance and self-realization. The satisfac⁃ tion of audience needs has a strict causal logic relationship, and different needs show different characteristics.【 Innovation/limitation】 Based on the comment content, the audience needs are analyzed, and the application of the event graph is expanded. In view of the limitations of case studies, it is still necessary to expand the intangible cultural heritage video comment corpus in the future.