This study used CTQ-SF, PLC-C, PTGI and AAS questionnaires to evaluate the mediating role of attachment from childhood trauma to PTSD and PTG among 1421 college students in 5 colleges in a province as subjects. Through correlation analysis by SPSS, structural equation modeling analysis and Bootstrap method by Mplus, the results highlighted that childhood trauma positively predicted PTSD directly and negatively predicted PTG directly. Furthermore, it could negatively predict PTSD and positively predict PTG under the mediation of closeness-dependence, and positively predict PTSD and negatively predict PTG under the mediation of attachment anxiety. Therefore, we concluded that college students' childhood trauma had an important influence on PTSD and PTG, and attachment played a partially mediating effect from childhood trauma to PTSD and PTG. Implications for future research and attachment-based clinical intervention are discussed.