Nowadays, social media has become an indispensable part of information dissemination, and its role and influence are constantly shaping the information ecology of today's society. At the same time, the attention of crisis events on social media continues to increase, which is of great significance for crisis management and response. This paper aims to take Twitter as an example to explore the role and influence of social media in crisis communication, and to analyze its role in instant transmission, information transmission speed, public opinion guidance, public relations channels and emotional connection in crisis events through literature review and case analysis. This paper aims to reveal the function mode, communication effect and coping strategy of social media in crisis communication and provide theoretical support and practical reference for improving public crisis awareness and crisis coping ability. At the same time, this paper provides reference for establishing an effective crisis communication management mechanism, which is helpful to improve the public's cognition and understanding of crisis events.