Ducted-fan unmanned aerial vehicle (UAV) is very beneficial in many civil and military applications. It has a good operational flexibility similar to helicopter. Normally, the ducting of high speed spinning fan is done for several reasons; the duct produces lift, it provides higher static thrust when compared to a bare fan of the same diameter, substantial noise level from a spinning fan or rotor can be suppressed, and it increase the safety level for both of the system and the user. However, the main challenge is to understand the aerodynamic characteristic of this vehicle. In this paper, computational fluid dynamic (CFD) is used to study the airflow and aerodynamic characteristic on a new configuration of ducted-fan UAV.