The proposed method is intended to adjust the electrode potentials used in deep brain stimulation (DBS) with the consideration of both tissue transform and thermal effects caused by stimulation. During a typical DBS process, it is essential, for an effective treatment, to control the stimulation strength and region with varied applied electrode potentials. Some previous studies have been devoted for numerical simulations to find suitable electrode voltage levels for pre-desired stimulated strength and region. These studies consider only one of the two complexity factors due to the intrusion of the DBS lead: 1) a layer of extracellular fluid and giant cell often formed around the DBS leads, called the peri-electrode space and 2) thermal effects. These two factors should both be considered in finite element electromagnetic analysis (FEA), which provides the means to adjust electrode potential for the originally-desired DBS region-called the volume of tissue activated (VTA). Simulation results show that there should be a limiting stimulation voltage to meet the temperature constraint.