Abstract: The aerodynamic characteristic of UAV(unmanned air vehicle) was studied based on the method of combining aerodynamic prediction with wind tunnel test. The contrast tests of longitudinal moment for different anhedral and incidence of V-tails were conducted to confirm the empennage distribution and to find out that the anhedral of V-tail affected the longitudinal moment greatly. The causes of turnup moment curves were analyzed. The components and the whole airplane aerodynamic tests were carried out, and the methods for calculating the aerodynamic characteristic of V-tail UAVs were given. Furthermore, the cause of the difference between the two methods was analyzed. The aerodynamic characteristic of a UAV was optimized by adjusting the incidence of empennage. In the wind tunnel test, the aerodynamic prediction methodology is testified reliable to be used to calculate the aerodynamic characteristic of the other airplane with the same aerodynamic configuration.