The increasing complexity of the electronic devices and the challenges involved in satisfying the needs of higher power and energy determine us to pay an important attention on supercapacitors behaviour study. Even if their energy density is about ten times lower than the energy density of the batteries, supercapacitors offer new alternatives for applications where energy storage is needed. This paper discusses one simplified PSpice model for supercapacitors. The proposed method for computing the parameters of the equivalent electrical circuit is based on experimental data achieved in different test conditions. The improved parameter identification method used provides a satisfying accuracy if the profiles of the charge/discharge/self-discharge of the supercapacitors are known.