This paper presents a study on an ultra-precision electrospray process for direct and localized integration of functional nanomaterials on microelectromechanical systems (MEMS). Electrospray deposition (ESD), owing to its sub-μm coating resolution, is widely used for surface protection, electrode patterning, and additive manufacturing. In addition, the ESD process is compatible with various materials. By optimizing the type of solution, voltage, and distance between the nozzle and surface, ESD can coat structures smaller than 1 mm. However, it becomes challenging when the feature sizes reduce to microscale, thus limiting its use in MEMS fabrication. Herein, we investigate the influence of changes in the electrical grounding condition of conducting microstructures and validate the particle deposition pattern and the effect of the applied voltage on the electrospray process. We present simulation and experimental verification of the proposed process, and the results show promising potential for integrating functional nanoparticles with MEMS components.