Why can some people make extraordinary sacrifices for the ingroup? For instance, many sacrificed their lives for their country during wars and saving others’ lives in peace time, while terrorists took their own lives for their faith such as the act of attacking on the World Trade towers. We propose that social identity plays an important role in such sacrifices. In the present study, we aimed to examine the effect of identification with ingroup on willingness to sacrifice one’s life for the ingroup and its members. Furthermore, we investigated the psychological mechanisms underlying this effect by investigating the mediating role of positive affects toward the ingroup and denial of possible harm by ingroup as well as the moderating role of belief of invulnerability of oneself and the group in the context of Chinese cultural background. The present research employed a questionnaire survey using four well established scales and one purposely designed scale with 467 university students from three colleges of Shanghai. The measured variables were identification with ingroup, positive affects toward ingroup, denial of possible harm by ingroup, willingness to sacrifice life for ingroup and belief of invulnerability of oneself and ingroup. The Cronbach’s alpha coefficients for the above measures were from 0.706 to 0.904, indicating satisfactory measurement reliabilities. Results of confirmatory factor analysis also suggested satisfactory discriminant validity of the measurement. Structural equation modeling (SEM) and moderated mediation analysis were employed to test the hypotheses. In line with our predictions, the findings show supporting evidence for our hypotheses. First, identification with ingroup predicted willingness to sacrifice one’s own life for the group. Second, both positive affects toward the ingroup and denial of possible harm by ingroup fully mediated the effect of identification with ingroup on willingness to sacrifice, while positive affects were more strongly associated with willingness to sacrifice for ingroup. Furthermore, positive affects partially moderated the effect of identification with ingroup on denial. Third, belief of invulnerability of oneself and ingroup moderated the effect of positive feelings on willingness to sacrifice. Theoretical and practical implications are discussed.