The Yaan earthquake in 2013, another destructive natural disaster that occurred in Sichuan, China after the Wenchuan earthquake in 2008, has caused widespread loss of life and property. Adolescent survivors of this earthquake experienced significant psychological reactions, and posttraumatic stress disorder (PTSD) is often considered to be the most frequent one in the aftermath of disasters. Many researchers, to date, have examined the reason for the high prevalence of PTSD, and found that the severity of traumatic exposure was a precondition of PTSD. However, not all the traumatized people been exposed to traumatic events would experience PTSD. This can be attributed to the differences in cognitive reaction. The shattered world assumption suggests that the extent of core beliefs being challenged by traumatic event can activate the development of different cognitive reactions and elicit the development of PTSD. According to the cognitive evaluation theory, people exposed to traumatic events can also take different strategies to cope the traumatic clues, and negative coping strategies, such as intrusive rumination, are important risk factors for PTSD. What calls for special attention is that both the shattered world assumption and the cognitive evaluation theory emphasize the effect of cognition after traumatic exposure in the developing process of PTSD, and they also share the same limit in clinical intervention for PTSD by ignoring the role of emotion. Thus, some researchers suggest that more attention should be paid to people’s emotive reactions, such as fear, in the PTSD study. And based on the model of fear network, traumatic exposure can make people experience more fear for the trauma, which may in turn increase the likelihood of the appearance of PTSD. While traumatic exposure, core beliefs challenge, intrusive rumination and subjective fear were theoretically speculated as important risk factors, the specific paths how traumatic exposure elicits PTSD by these factors are unclear. Furthermore, the predictive utility of these risk factors has not been evaluated in an integrated model, and the relationship between cognitive reactions and emotive reactions in the developing process of PTSD has not been examined. In addition, previous researchers mainly studied the general adults or college students, and few focused on the adolescent survivors after disaster. Regarding the above limitations, the current study aimed to explore the role of core beliefs challenge, intrusive rumination, and subjective fear in the association between traumatic exposure and PTSD among adolescent survivors six months after the Yaan earthquake. 310 adolescent survivors were selected from several junior and senior middle schools in the county of Lushan, the area most severely affected by the Yaan earthquake. Participants completed Traumatic Exposure Questionnaire, Subjective Fear Questionnaire, Core Beliefs Inventory, The Event Related Rumination Inventory and The Revised Child PTSD Symptom Scale six months after the Yaan earthquake. The results found that both the mean level and the prevalence of PTSD were relatively low. The mean level of PTSD of male students was lower than that of female students, and the mean level of PTSD of grade 1 students in senior middle school was higher than that of all the other grade students who participated in the survey. The analysis of structural equation model found that the severity of traumatic exposure had positive effect on PTSD by core beliefs challenge and by that via the multiple mediator effect of intrusive rumination. Moreover, traumatic exposure could positively affect PTSD by the severity of subjective fear via the multiple mediator effect of intrusive rumination. However, the severity of traumatic exposure had no effect on PTSD by intrusive rumination or subjective fear.