Abstract Background A violent attack on medical staff in Guangdong Province, in which a female doctor at Longmen County People’s Hospital (LCPH) was severely injured by a knife-wielding patient, has drawn significant public attention to the phenomenon of hospital violence and initiated discussions on how to resolve violence in hospitals. Social networking sites, such as Sina Weibo, a Chinese version of Twitter, have played a role in this public debate. The incident at LCPH provides an opportunity to examine how Weibo has been used in the debate about violence against medical staff in China. Methods Using the Sina Weibo’s built-in search tool, we established a dataset of 661 Chinese-language micro-blogs containing the search terms: Longmen (“龙门”), doctor (“医生”), and slash (“砍”) that were posted between July 15, 2015, the date of the violent incident at LCPH, and August 15, 2015. We performed a content analysis of the micro-blogs to examine: users’ demographics, attitudes toward the injured doctor and the attacker, possible reasons for the hospital violence, and proposed measures for preventing doctors from violent incidents. Results 73.2% of the micro-blogs were sent by individual Weibo users, and 26.8% were posted by organizations. For individual users, around 10.0% described themselves as either doctors or healthcare providers, but users from the legal profession were rarely identified. Moreover, only 3 micro-blogs proposed concrete strategies for preventing hospital violence, and nearly 10.0% of micro-blogs expressed regrets about entering a medical career and attempts to quit medical positions. In general 56.3% of micro-blogs showed sympathy for the injured doctor, while less than 25.0% of micro-blogs explicitly condemned the attacker’s behavior. Conclusions Weibo users played a role in distributing news information about the violent incident at LCPH; however, the legal perspective is inadequately discussed in the debate, and discussion of constructive measures for protecting doctors and preventing hospital violence was rare. Our research suggests that critical challenges for the Chinese health care system will remain or become worse if no effective measures are implemented to prevent hospital violence.