Selfie, which refers to “a self-portrait photograph of oneself (or of oneself and other people), taken with a camera or a camera phone held at arm's length or pointed at a mirror, which is usually shared through social media”, prevails on the social Internet recently. A substantial body research revealed that online self-presentation behaviors could contribute to variety of positive consequences. Nevertheless, few studies examine the antecedent factors and little know about the underlying mechanism of selfie posting behaviors. The current study suggested three propositions. Firstly, based on the impression management theory, self-perceived appearance attractiveness may be a potential facilitator of selfie posting behaviors. Thus, the first purpose was to investigate the effect of self-perceived appearance attractiveness on selfie posting behaviors. Secondly, according to fitness-related evolutionary theory, self-perceived appearance attractiveness was associated with extraversion, which in turn was associated with selfie posting behaviors. It could be hypothesized that extraversion would mediate the relationship between self-perceived appearance attractiveness and selfie posting behaviors. In addition, exhibitionism, which refers to a disposition of attracting others' attention by presenting private lives publicly, may have a potential influence on the associations. Therefore, we also aimed to examine whether exhibitionism would have a moderating role on the direct effect of self-perceived appearance attractiveness and the indirect effect of extraversion on selfie posting behaviors. A sample of 377 students from universities in Beijing, including 255 females and 115 males was recruited to complete several self-report questionnaires, including Attractiveness Questionnaire, Extraversion Inventory, Exhibitionism Questionnaire and Selfie Posting Behaviors Questionnaire, together with their demographic information. Then, a hypothetical moderated mediation model was formulated to examine the effects of self-perceived appearance attractiveness on selfie posting behaviors and the mediating role of extraversion, as well as the moderating role of exhibitionism. The results demonstrated that: (1) After controlling for the effect of gender, self-perceived appearance attractiveness had a positive prediction on selfie posting behaviors. (2) Extraversion could partially mediate the relationship between self-perceived appearance attractiveness and selfie posting behaviors. (3) The indirect effect of which self-perceived appearance attractiveness on selfie posting behaviors through extraversion was moderated by exhibitionism. Specifically, with the increasing of the level of exhibitionism, the conditional mediating effect of extraversion changed from non-significance to significance. Taken together, the findings indicated that with a high level of exhibitionism, individuals who perceived their appearance attractive tend to behave extrovertly, leading to post more selfies on the social network. In contrast, with a low level of exhibitionism, self-perceived attractive people failed to facilitate selfie posting behaviors through extraversion. In conclusion, these results could address the issue that what works for whom, extending previous studies in some aspects. From the theoretical perspective, it was one of the first studies that combine self-assessed physical features, personality disposition and self-presentation behaviors, which could provide a constructive perspective to unravel the underlying mechanism. Meanwhile, this study found that extraversion could link self-perceived appearance attractiveness and selfie posting behaviors, and exhibitionism served as a potential moderator towards the mediating relationship, which is greatly helpful to advance the understanding of selfie posting behaviors.