Background People who had died by suicide always being associated with negative emotions and even mental disorders. Understanding mechanisms underlying the association between quality of life (QOL), hopelessness, and suicide are of great significance. In this study, we aimed to test a model in which the QOL-suicide relationship was mediated by hopelessness and moderated by impulsivity.Methods Participants (N = 484, including 242 suicide deaths and 242 matched controls) were rural residents 60 years of age and older, randomly selected from 12 rural counties in China using a two-stage stratified cluster sampling method. Data were collected with standard psychological autopsy technique from informants (n = 968). The outcome variable was a suicide death. QOL, hopelessness, and impulsivity were assessed using validated scales. The proposed relationships were tested using mediation and moderated mediation models.ResultsOf the total sample, 55.8% were men with a median age of 75.5 years. Results from the moderated mediation analysis indicated that QOL was negatively associated with suicide (beta = −0.141, p < 0.01); this association was mediated by hopelessness (indirect effect: beta =0.578, p < 0.01), accounting for 73% of the total effect. Impulsivity significantly moderated the mediation effect from QOL to hopelessness (beta =0.005, p < 0.01).Conclusions Study findings have confirmed the negative association between QOL and suicide with psychological autopsy data, and demonstrated the role of hopelessness in mediating the QOL-suicide relation that is further modified by impulsiveness. These findings depend on our understanding of the suicide epidemiology among the elder in rural China and provide information much needed for suicide prevention.