Background Most epidemiological studies on adolescent survivors' mental health have been conducted within 2 years after the disaster. Longer-term psychological consequences remain unclear. This study explored psychological symptoms in secondary school students who were living in Sichuan province 6 years after the Wenchuan earthquake. Methods A secondary data analysis was performed on data from a final survey of survivors conducted 6 years after the Wenchuan earthquake as part of the five-year mental health and psychosocial support project. A total of 2641 participants were divided into three groups, according to the level of traumatic experience exposure during the earthquake (0, 1, and 2 or more). ANCOVA was used to compare the mean scores of the Symptom Checklist-90 (SCL-90) among the three groups, adjusting for covariates such as age, gender, ethnicity, having a sibling, parents’ divorce, and socio-economic status. Logistic regression analysis was used to identify relationships between the traumatic experiences and suicidality after the disaster. Results Having two or more kinds of traumatic experiences was associated with higher psychological symptom scores on the SCL-90 (Cohen's d=0.23–0.33) and suicidal ideation (OR 1.98, 95% CIs:1.35–2.89) and attempts (OR 3.32, 95% CIs:1.65–6.68), as compared with having no traumatic experience. Limitations Causality cannot be inferred from this cross-sectional survey, and results may not generalize to other populations due to convenience sampling. Conclusions Severely traumatized adolescent survivors of the earthquake may suffer from psychological symptoms even 6 years after the disaster. Long-term psychological support will be needed for these individuals.