The effective communication of scientific information in popularization short videos requires the collaboration of multiple modal discourses. The integration，complementarity，and reinforcement among these multimodal discourses facilitate audiences’understanding of complex scientific knowledge. Based on a multimodal discourse analysis framework，this study explores the narrative strategies of science popularization short videos intending to enhance their effectiveness. This study selects thescience popularization short videos from the Bilibili account“Huazha Hua Xiaolao”as the research object，analyzing the interaction among visual，linguistic，and auditory modal discourses within the videos. Findings indicate that multimodal narratives enhance the narrative expressiveness of science popularization short videos，stimulate emotional expression，and expand cross-media storytelling capabilities. On this basis，this paper proposes the following narrative strategies：scene-based narrative contextual optimization，deep integration of emotions and narrative cues，and cross-platform multimodal storytelling with full-link dissemination. These strategies aim to provide theoretical and practical guidance for the creation and dissemination of science popularization short videos.