Abstract: High-wing aircraft generally has a big landing gear fairing, thereby its shape needs to be designed carefully so as to reduce drag as much as possible. In order to understand the aerodynamic effect of landing gear fairing and guide the following fairing shape redesign, a contrast is made between the configurations with fairing and the otler without fairing. Considering the landing gear layout restraints, a NURBS parametric modeling method within CATIA is proposed and implemented to redesign the shape of landing gear fairing. CFD results indicate that the drag is reduced by 1.9 Counts, about 27% of the whole drag reduction margin. Moreover, in order to understand the fairing effect more clearly, a deformation without landing gear constraints is performed. The drag reduction can reach to 3.4 Counts, and results show the effect of fairing can be concluded as the disturbance between fairing and wing.