Objective To understand frontline nurses′ experience of participating in Balint-group-based activities in the context of a war against the COVID-19 outbreak. Methods Using the objective sampling method, 18 nurses working in the frontline of a war against the COVID-19 outbreak and having participated Balint-group-based activities were invited to have semi-structured interviews. Then the recorded data were analyzed and collated according to the Colaizzi 7-step analysis method. Results Four themes were refined: The Balint Group provided a platform for venting negative emotions (anxiety, nervousness, fear, self-blame, guilt, or loneliness); participating in the Balint Group increased the sense of belonging and peer support;the Balint Group broadened the participants′ perspectives and views of a problem from multiple facets; the Balint Group could more easily mobilize the enthusiasm of the participants and allow them to actively express their inner feelings. Conclusion The Balint group approach alleviates the negative emotions of frontline nurses in the fight against the epidemic, helps them adjust to psychological crisis, and provides a reference for psychological intervention for frontline nurses handling public health emergencies.