In recent years, quadrotor Unmanned Aerial Vehicles (UAVs) were widely developed thanks to many advantages of this kind of UAV in vertical take-off and landing, hovering ability and maneuverability in a narrow area. The characteristics of dynamic flight and control of quadrotor were reported in several studies. The considered object in this paper is a V-1 quadrotor that has payload of 2 kg, ceiling of 300 m and operation range of 5 km. The study on aerodynamic characteristic is an important part in the design process of the V-1 quadrotor that allows optimizing the flight performance as well as evaluating the stability of the UAV. CFD simulations were carried out with the UAVs 3D full scale model in order, deeply, to understand the streamlines pattern and the aerodynamic interaction between the four propellers. The aerodynamic analysis of the rotary wing in take-off/hovering was performed using the Multiple Reference Frame (MRF) model of ANSYS Fluent software. The obtained results about aerodynamic forces, interaction among the propellers are the basis for the detailed design of V-1.