To the problem of mathematical modeling of taxiing of UAVs with articulated landing gear, a detailed analysis is made to the movement characteristics of the landing gear buffer. Considering the wheel rolling friction characteristics, the main wheel differential braking characteristics and the lateral deflection of the wheel, also taking into account of the aerodynamic force and its torque, and based on the theory of rigid body dynamics and kinematics, we established a six-degree-of-freedom nonlinear full-scale mathematical model, which can fully reflect the physical motion characteristics of the taxiing of UAVs. Taking a certain UAV as an example, we carried out mathematical modeling and simulation analysis. The simulation results show that the established six-degree-of-freedom nonlinear full-scale mathematical model can truly reflect the physical movement characteristics for UAV taxiing.