Optimization of electrostatic sensor electrodes plays a significant role to achieve more homogenous spatial sensitivity. Particle swarm optimization (PSO) is a simple method that has attracted many attentions in recent years. In this paper, the physical sizes of several electrodes for electrostatic sensors are optimized using the PSO technique. Spatial sensitivity of electrode is considered as objective function in this method. Additionally, the thickness and length of electrode are described as physical characteristics of electrode, which need to be optimized. In order to verify this optimization method, different electrodes are applied in laboratory. The optimal value of thickness and length of electrode according to the optimization and experimentation are 5mm and 6mm, respectively. As a result, there is a great agreement between the optimization and experimental results.