During the COVID-19 epidemic, the community emergency management model led by government departments and participated by multiple subjects has become an important measure for epidemic prevention and control at the grass-roots level in China. Among them, urban residents, as one of the main bodies of emergency response, has unique advantages in participating in community emergency governance. However, in practice, the effectiveness of emergency management of this group is greatly reduced due to various difficulties. In addition, there is a complex mechanism behind the difficulties faced by this group, which has received little attention in previous studies. Based on grounded theory, we conducted in-depth interviews with 35 Shanghai community emergency responders, and sorted and coded the interview text. After inductive analysis, we obtained the dilemma and related mechanism of urban residents’ response to community governance in the context of public crisis. The study found that the dilemma of urban residents’ emergency response can be divided into two parts: internal and external. The internal dilemma can be subdivided into team dilemma (including shortage of staff and uneven personnel quality) and individual dilemma (including family burden, workload and negative emotions). The external dilemmas are reflected in policy, institutional dilemmas (including institutional rigidity, lack of materials and lack of publicity) and environmental dilemmas (including bad weather and public doubts). On this basis, policy and system dilemmas act on team dilemmas and environmental dilemmas, environmental dilemmas act on individual dilemmas, and individual dilemmas act on team dilemmas. The corresponding theoretical model is further constructed and improved, which is beneficial to the academic community to further deepen the research in related fields.