Short video platforms have developed as pivotal arenas for academic communication and public engagement. Consequently, a growing number of academic journals have established official accounts on these platforms to disseminate research outputs and enhance public visibility. This trend has attracted considerable scholarly attention, with existing studies mainly focusing on science and technology journals. In contrast, the digital practices of social science journals on short video platforms remain largely unexplored. This study therefore aims to develop a comprehensive analytical framework for digital narratives that integrates subject, mechanism, and effect, and applies it to a multi-platform "narrative field" encompassing the top 30 CSSCI journals ranked by WeChat public accounts dissemination data. A cross-platform comparative analysis is conducted using data collected from WeChat Channels, Bilibili, and Douyin. This study conceptualizes the dissemination as a complex system with three elements: the dynamics primarily driven by the authority and credibility of the accounts, the specific translation pathways and stylistic narrative strategies employed in the process, and the audience reception and engagement. The first element is related to audience attention, the second one determines the depth and sustainability of audience engagement, and the third one refers to audience feedback and dissemination effectiveness. Together, these elements form a dynamic "content-context-feedback" chain. Narrative subjects employ distinct discourse to reconstruct academic authority and garner attention. They utilize various narrative mechanisms to encode and recode academic content, balancing comprehensibility with scholarly credibility. Simultaneously, platform algorithms modulate the visibility and interactivity of academic short videos. This study reveals several bottlenecks in current digital practices of social science journals. Regarding narrative subjects, there is a notable lack of official verification, compromising the perceived credibility. The narrative process often fails to provide deep interpretation of academic content in some circumstances, and the current dissemination strategies are highly homogenized. Concerning the narrative effect, user feedback remains sparse, and audience stickiness is weak. Enhancing the effectiveness of the digital narrative practices needs a concerted endeavour. We suggest that social science journals pursue a further overall improvement across three core elements: authority, comprehensibility, and effectiveness. This necessitates strengthening the authority of the narrative subjects, diversifying the dissemination strategies, enhancing the innovation and differentiation of narrative mechanisms, encouraging audience participation through a combination of expert-generated-content and user-generated-content and developing an agreeable framework to measure the conversion of platform traffic into knowledge adoption, including journal subscriptions and citations. In conclusion, this study shows that the interrelationship between subject and audience has the potential to be a significant perspective in analyzing the digital transformation of social science knowledge and ideologies. We suggest that social science journals develop a diversified cross-media portfolio of strategies: print publications to ensure academic depth, WeChat official accounts to increase visibility, and short video platforms to broaden social reach—thereby achieving both greater depth and expanded breadth. This study advances theoretical and empirical understandings of digital publishing and provides actionable guidance for social science journals to cultivate a sustainable and recognizable knowledge brand on short video platforms.