To solve the problem of two-dimensional trajectory tracking of fixed-wing UAV under crosswind conditions,a trajectory tracking algorithm with adaptive guidance length is proposed based on nonlinear guidance law.Firstly,a kinematic model of the UAV after introducing wind disturbance is established,the nonlinear guidance law with a fixed guidance length is theoretically analyzed,and its wind resistance performance is discussed.Then,based on the performance and flight velocity of the UAV itself,a method of adaptive guidance length is proposed,and the side offset distance integral is introduced into the lateral acceleration command to offset the crosswind interference.To solve the problem that the trajectory error of the UAV is too large when the waypoint is switched,an arc waypoint switching strategy is designed.Finally,the numerical simulation is carried out in the case of crosswind interference.The results show that the method can effectively suppress crosswind interference,and has high tracking accuracy at waypoint switching.The precise tracking of the desired trajectory of the fixed-wing UAV under the condition of crosswind interference is realized.