In the phishing email literature, recent researchers have given much attention to individual differences in phishing susceptibility from the perspective of the Big Five personality traits. Although the effectiveness and advantages of the phishing susceptibility measures in the signal detection theory (SDT) framework have been verified, the cognitive mechanisms that lead to individual differences in these measures remain unknown. The current study proposed and examined a theoretical path model to explore how the Big Five personality traits, related knowledge and experience and the cognitive processing of emails (i.e., mail elaboration) influence users' susceptibility to phishing emails. A sample of 414 Chinese participants completed the 44-item Big Five Personality Inventory (BFI-44), Mail Elaboration Scale (MES), Web Experience Questionnaire, Experience with Electronic Mail Scale, Knowledge and Technical Background Test and a demographic questionnaire. The phishing susceptibility measures were calculated after the participants finished an email legitimacy task in a role-playing scenario. The results showed that the general profile of the "victim personality" included low conscientiousness, low openness and high neuroticism, and Internet experience and computer and web knowledge played an important role. All of these factors have significant indirect effects on phishing susceptibility by influencing mail elaboration. Moreover, the probabilities of checking for further information or deleting the email reflect the sensitivity of email judgment. These findings reveal the mediating role of cognitive processing between individual factors and phishing susceptibility. The theoretical implications of this study for the phishing susceptibility literature and its applications to phishing risk interventions or training programs are discussed.