China's marriage registrations have declined substantially, dropping from 13.47 million couples in 2013 to 6.1 million in 2024. This study examined sentiment and moral elements underlying 219,358 marriage-related posts from Weibo and Xiaohongshu using large language model (LLM)-assisted content analysis. Drawing on Shweder's Big Three moral ethics framework, posts were coded for sentiment (positive, negative, neutral) and moral elements (autonomy, community, divinity). Results revealed platform differences: Weibo leaned toward positive sentiment, while Xiaohongshu was predominantly neutral. Most posts lacked explicit moral framing. However, when moral elements were invoked, significant associations with sentiment emerged. Posts invoking autonomy and community were predominantly negative, whereas divinity-framed posts tended toward positive sentiment. These findings suggest that concerns about both personal autonomy constraints and communal obligations contribute to negative marriage attitudes in contemporary China, offering insights for culturally informed policies addressing marriage decline.

翻译：中国婚姻登记数量显著下降，从2013年的1347万对降至2024年的610万对。本研究采用大语言模型辅助内容分析方法，对来自微博和小红书的219,358条婚姻相关帖文进行情感与道德要素分析。基于Shweder的道德伦理三元理论框架，帖文被编码为情感（积极、消极、中性）与道德要素（自主性、社群性、神性）。结果显示平台差异：微博倾向于积极情感，而小红书以中性情感为主。多数帖文缺乏明确的道德框架。然而，当涉及道德要素时，其与情感呈现显著关联：涉及自主性与社群性的帖文以消极情感为主导，而涉及神性框架的帖文则倾向于积极情感。这些发现表明，对个人自主性限制与社群义务的双重关切共同构成了当代中国消极婚姻态度的影响因素，为制定应对婚姻率下降的文化适应性政策提供了参考依据。