Online social media has become one of the most important ways for authoritarian regimes to maintain their resilience. When authoritarian regimes are faced with challenges, what options would they take to defend their regime? This paper takes Hong Kong protests and early-stage COVID-19 as two examples to study how the Chinese official Weibo accounts responded to these crises. This paper leverages text analysis to mine, explore, and learn from Weibo posts related to these crises. This paper seeks to answer how do these Weibo accounts change during and after the crises, including their word frequency, topic, keywords, and sentiment scores.