The “COVID-19” pandemic has not only posed severe global public health challenges but has also profoundly impacted social mental health and public opinion dynamics. This study aims to explore the similarities and differences in public attention foci and emotional expressions in China’s northern and southern regions during the post-pandemic era, thereby revealing the regional characteristics of human behavior, decision-making, and social dynamics in complex and uncertain environments. Based on large-scale Weibo text data, we integrate theories from cognitive stress, cultural psychology, and computational social science. We employ the BERTopic model, which leverages large pre-trained language models (BERT), for topic modeling and combine it with a sentiment lexicon for emotional analysis. The findings indicate that, regarding problem-focused coping, the northern public tends to focus more on the dynamic adjustments of epidemic prevention policies and their impact on the education sector. In contrast, the southern public demonstrates sustained attention to the economic recovery process and the evolving epidemic situation. For emotion-focused coping, both northern and southern publics generally exhibit a convergence towards positive emotions, though subtle differences exist in the intensity of specific negative emotional expressions. These findings not only deepen our understanding of how distinct socio-psychological response mechanisms, influenced by cultural norms and economic structures, manifest in online discourse during crises. They also provide empirical evidence for formulating differentiated public policies and crisis management strategies in the future, underscoring the critical role of interdisciplinary research in addressing complex societal challenges.