Traditional manual exterior wall spraying faces safety risks, high costs, and operational limitations. This research focuses on drone control technology for vertical surface spraying. The mobility of drone enhances adaptability to complex walls, while remote operation improves safety. The tether simultaneously delivers power that originates from a ground generator and paint that is supplied from a ground-based system, which significantly extends endurance and reduces the payload of drone because it only carries spraying actuators. Key components were selected based on spraying requirements and unmanned aerial vehicle (UAV) weight constraints, after which motor selection was finalized. This enabled dynamic modeling and disturbance analysis. Using these parameters, a Simulink dynamic simulation model and a cascade PID controller were developed. Simulations confirmed that the system responds rapidly and converges errors effectively. A physical prototype that integrated all subsystems was built. Tests verified that the system spraying positioning accuracy that remains within ±0.15 m. The tethered approach separates paint and power sources from the UAV, which reduces its load capacity demands while ensuring operational feasibility and stability for exterior wall spraying applications.