The performance of dielectric elastomers is affected by temperature and deformation, but very few models account for the effect of both factors. Recent experiments showed that the dielectric constant of the most widely used dielectric elastomer varies significantly with respect to temperature and deformation. We propose a model to study the influence of changes in dielectric constant on the electromechanical stability of dielectric elastomer. The model predicts the stability criteria with physical interpretation of its dependence on dielectric constant and electrostrictive coefficient. The numerical simulation indicates that the stress due to electrostriction relies on the temperature and deformation dependent dielectric constant and contributes to enhance the stability of the dielectric elastomer. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013