Objective: To assess the association of adverse experiences and subsequent incidence of depressive symptoms among middle school students in Liangshan, so as to provide a basis for preventing the occurrence of depression symptoms among middle school students. Methods: In October 2021, a convenient sampling combined with cluster random sampling method was employed to select 888 students from three high schools (junior first year and second year, senior first year) in Liangshan for a questionnaire survey. In March 2023, a followup survey was conducted to collect data on adverse experiences (such as school bullying, domestic violence, and lack of parental understanding). Depressive symptoms were assessed using the Chinese version of the Center for Epidemiologic Studies Depression Scale (CES-D). Logistic regression model analysis was used to examine the relationship between the number of adverse experiences at baseline and the incidence of depressive symptoms during the followup period. Results: The detection rate of depressive symptoms among middle school students was 9.4% at followup. School bullying (OR=2.26, 95%CI=1.37-3.73), domestic violence (OR=2.56, 95%CI=1.55-4.21), and lack of parental understanding (OR=1.91, 95%CI=1.15-3.16) at baseline were positively associated with the incidence of depressive symptoms at followup (P<0.05). Compared with participants with no adverse experiences at both baseline and followup, those with adverse experiences at both baseline and followup were more likely to exhibit depressive symptoms at followup, regardless of the type of adverse experiences (P<0.01). The incidence of depressive symptoms increased with the increase of baseline adverse experiences (P<0.01). Compared to the participants with no adverse experiences at both baseline and followup, those with adverse experiences at baseline but not at followup did not show a statistically significant difference in the likelihood of developing depressive symptoms at followup (OR=0.78, 95%CI=0.13-4.80, P>0.05). Conclusions Adverse experiences increase the risk of developing depressive symptoms among middle school students. Participants who have reversed adverse experiences show no increased risk of depressive symptoms compared to those with no adverse experiences. Measures should be taken to prevent the occurrence of depression symptoms among middle school students based on their adverse experiences during their middle school years.