This study focuses on the case of “Xiao Xie, who was subjected to domestic violence 16 times over two years,” and explores the evolution of public sentiment and the shift in core topics within online discourse by integrating BERT-based sentiment analysis and word cloud techniques. The findings reveal that the public opinion process follows three distinct stages: the Outbreak stage, the Spread stage, and the Recession stage. Public sentiment transitions from anger and condemnation to rational reflection, ultimately culminating in discussions centered on legal and institutional reform. Negative emotions drive the rapid dissemination of information in the early stage, while emotional differentiation in later stages steers public discourse from individual case critique toward broader societal issues such as domestic violence governance and judicial reform. This study uncovers the social-psychological mechanisms underlying the evolution of public opinion and proposes targeted strategies for opinion guidance and governance at each stage. The findings provide both empirical data and theoretical insights to support the optimization of domestic violence response and broader social governance.