In the contexts of direct violence, adversarial groups repeatedly aggress against each other harms or kills a great number of people. Such contexts often leave the parties involved with a deep sense of victimhood, “which group suffer more” is an important question. Each group involved in the conflict tries its best to claim that it has suffered more than the out-group. Moreover, this competition over the quantity of suffering also implies some dispute over the illegitimacy of the suffering. Then, a group’s motivation and consequent efforts to establish that it has suffered more than its adversaries are called inter-group competitive victimhood, CV. In the contexts of direct violence, CV is prevalent regardless of the group status and group power. Once the group has constructed its biggest victim role, the members would share this kind of belief, and reject, deny and refuse heterogeneous information threatened. CV reflects the obvious egocentric tendency when in-group evaluate their injuries. There are several dimensions of victimhood over which groups may compete, they are physical suffering(groups may quantify suffering and portray their in-group as having endured a larger share of the overall suffering), material suffering(groups often compete over material resources, such as housing, education, and employment), cultural suffering(conflicting groups may call attention to their sense of cultural deprivation or threat of cultural extinction, such as loss of language, unique religious, way of life), psychological suffering(psychological distress, emotional pain, and subject wellbeing), illegitimacy of suffering(injustice of their suffering), the sense of victimization, the ways be treated after conflicts (whether they have received adequate attention concerning their needs compared with victims in the other group). Groups may stress one or more dimensions depending on their different needs. Disadvantaged groups may highlight obvious and objective damages, while advantaged groups perhaps highlight the subjective aspects, claiming that their behaviors involved in the conflict were forced. Constructing the biggest victim role is a social constructing process. We reviewed the various psychological bases and motivations behind CV, specifically, including collective sense of victimhood (a mindset shared by group members that results from a perceived intentional harm with severe consequences), cognitive attribution of responsibility(group members are likely to cast their in-group in the role of the victim and out-group in the role of the perpetrator), biases memories about inter-group conflicts(selective and biased information processing and remembering), group’s motivations to maintain its moral acceptance or restore their power, and other psychological bases(group emotions results from conflicts, such as anger, fear, anxiety). The existence of CV serves various functions. As far as in-group is concerned, CV contributes to conflicts’ escalation, increases in-group identification, weakens responsibility of conflict, and obtains the supports from other non-involved groups. However, in term of out-group, such efforts of CV impede the process of inter-group forgiveness and reconciliation. Studies found that direct inter-group contact, and constructs both common victim identity and common perpetrator identity, the groups involved conflicts would lower the level of CV. There has been little systematic investigation on this kind of competition, therefore, in the future, more researches are needed to explore the mechanisms and multiple psychological factors, such as the positive effects of different indirect group contact, apology and compensation on CV. Researchers also need to explore the psychological mechanisms of CV between hostile groups, as well as the cognitive and evaluated mechanisms of the third group on who is the biggest victim.