Solid-state Mediator supercapacitors (SCs) are supposed to provide a high specific energy (25-30 Wh/kg) and high specific power (10-25 kW/kg). In addition, they are shape-flexible, hazard-free, and temperature insensitive. Mediator supercapacitors can be made into dual functional structural materials that store energy and endure mechanical loads. It is thus sensible to research the response of electrochemical processes to mechanical load and vice versa the response of mechanical properties to electrochemical processes. In the present research, a realistic model in the micrometer level is created with realistic geometries of the components including carbon fibers, carbon powders, solid polymer electrolyte, and mediator particles. The 3D model is shown as Figure 1. The realistic model is solved using COMSOL Multiphysics. The simulation describes the equilibrium process of the potential difference between the electrode phase and electrolyte phase under pressure. The total current of mediator supercapacitor increases with increasing pressures due to the increase of ionic conductivity of the electrolyte. The total current of mediator supercapacitor becomes constant at extremely high pressure because the supercapacitor is short circuit. Figure 2 is the design of the system which is used for evaluating the response of electrochemical properties of mediator supercapacitor to mechanical load. Through plane electrochemical impedance spectroscopy (EIS) analysis under different pressures is carried out. The experimental data show that the resistance dependence on the pressure agrees well with the modeling results. As such, the model can be used to design structural supercapacitors as structural components in an engineering system and predict the performance the structural supercapacitors under mechanical loading.