Abstract: The break-out of the COVID-19 in 2020 exposed a series of problems in china’s public crisis management. It is of great significance to study the impact mechanism of public crisis information response. In this paper, the Yancheng 3.21 Explosion in 2019 and the Tianjin 8.12 Explosion in 2015 are used in the double case study method. Through the analysis tools of sentiment analysis and topic clustering, the mechanism of how public crisis information response influences public behavior is constructed. The findings are as follows. (1) The public crisis information response mode has two types of crisis information response modes: binary-led and ternary-cooperative. (2) The degree of matching between public information supply and information demand will affect the public’s choice of reaction. When information supply does not match information demand, the public tends to adopt passive avoidance behaviors; when information supply matches information demand, the public tends to adopt positive coping behaviors. (3) There are reciprocal crisis evolution mechanism and active crisis evolution mechanism in public crisis event evolution mechanism, which are affected by the crisis information response mode. The results of this paper enrich the theory of crisis communication and have a guiding significance for public crisis managers.

Key words: public crisis, public reaction, crisis management, crisis information response