Existing research has not reached a consensus on the relationship between threat situations and individual prosocial behavior. Thus, this study takes novel coronavirus epidemic as a specific research situation and fills a gap in previous research from two perspectives: The time and the type of the threat situation. This study takes in-group identity and other-focused attention as intermediary mechanisms and proposes the dualpathway formationmechanism that affects individuals' willingness to donate and relevant moderator variables in the context of major public threats. The following findings are obtained for public threat scenarios, such as the novel coronavirus epidemic, facing both donors and recipients. 1) There is no significant difference in the impacts of epidemic severity at the location of the potential donors on their willingness to donate. 2) The opposite intermediary effect of in-group identity and other-focused attention masks the impact of epidemic severity at the location of the potential donors on their willingness to donate. The severity of local epidemic enhances individuals' in-group identity and then positively affects their wilingness to donate. On the other hand, it reduces the individuals' other-focused attention and then weakens their willingness to donate. 3) Regional cultural orientation moderates the positive intermediary effect of in-group identity and the negative intermediary effect of other-focused attention. Specifically, compared with partial individualism, when regional cultural orientation is partial colectivism, the positive impact of local epidemic severity on in-group identity can be enhanced and negative impact on other-focused attention can be reduced.