Background:Patients with major depressive disorder (MDD) usually have high risk of suicidality.Few studies have investigated the effects of stressful life events (SLEs) on the risk of suicide in Chinese patients who have developed MDD.This study aimed to investigate the impact of SLEs on suicidal risk in Chinese patients with MDD.Methods:In total,1029 patients with MDD were included from nine psychiatric hospitals to evaluate the impact of SLEs on suicidal risk.Patients fulfilling the Mini-Intational Neuropsychiatric Interview (MINI) criteria for MDD were included in the study.Patients were excluded if they had lifetime or current diagnoses of psychotic disorder,bipolar disorder,and alcohol or substance dependence.Depressive symptoms were assessed by the 17-item Hamilton Depression Scale (HAMD-17).The suicidal risk of MDD patients was determined by the suicide risk module of MINI.SLEs were assessed by the Life Events Scale.Results:No gender difference was found for suicidal risk in MDD patients.Patients with suicidal risk had younger ages,lower education levels,more drinking behavior,and lower marriage rate,and fewer people had child and more severe depressive symptoms than nonsuicidal risk group.High-level perceived stressfulness (HPS) and number of SLEs that patients were exposed to were significantly greater in patients with suicidal risk than patients without.In multivariate logistic analysis,HPS of SLEs (odds ratio [OR] =1.54,95％ confidence interval [CI]:1.16-2.05,P =0.003) and depressive symptoms (OR =1.08,95％ CI:1.05-1.11,P ＜ 0.001) were associated with suicidal risk even after adjustment of gender,age,marriage,drinking behavior,and childless.Conclusions:HPS of SLEs is associated with suicide risk in Chinese patients with MDD.Further suicide prevention programs targeting this risk factor are needed.Trial Registration:ClinicalTrials.gov:NCT02023567;https://clinicaltrials.gov/ct2/show/NCT02023567?term=NCT02023567&rank=1.