As a category of promising material, the membrane of dielectric elastomer (DE) sandwiched between two electrodes has the capacity for converting the electrical energy into mechanical energy, vice versa. Owing to the large deformation produced by relatively small stimulations, this elastomer is also component to function as a generator. Research on dielectric elastomer generators (DEGs) has achieved wide attention lately. The previous studies have indicated the performance of DE depends on the major dissipation processes including viscoelasticity and current leakage and also varies with temperature. However, very few works take these factors together into consideration when investigating the performance of DEGs. Therefore, in this study, a model that incorporates the temperature-dependent permittivity and shear modulus of DE, viscoelastic relaxation and current leakage is established. Then, based on a Carnot-shape conversion cycle, the performance of a dissipative generator made of very-high-bond (VHB) elastomer is researched in detail under different sampling temperatures. The parameters that characterize the performance of the generator are the energy densities of different kinds and conversion efficiency. Moreover, the mechanisms of typical failure modes including material rupture, loss of tension (LT), electrical breakdown (EB) and electromechanical instability (EMI) are studied with the influences of temperature to ensure that the DEG is operated in an allowable area. It can be concluded from the numerical results that the temperature plays an important role in the performance of the DEG, which could possibly improve its conversion efficiency.