Compared to traditional media, national parks increasingly rely on social media for information dissemination and knowledge popularization. Little research has explored the impact and mechanism of short video narratives on user engagement behavior in national parks. This paper collects 545 official short videos of national parks and classifies the video data using a combination of video processing technology and manual coding. It aims to explore the narrative elements of national parks and analyze their impact on user engagement behaviors by combining narrative transportation theory and elaboration likelihood model (ELM). The results of the study show that the narrative topic of the video has a significant effect on users’ liking and commenting behavior. The number of hashtags has a positive impact on user engagement behaviors, and narrative duration positively affects user liking and commenting behaviors. Compared to without background music, background music can increase users’ commenting behavior. This study expands the scope of theoretical research on promotion and marketing in national parks, as well as user engagement behavior and provides new perspectives on narrative transportation theory and the ELM. It also provides practical guidance for promoting and popularizing national parks.