This paper proposed a trajectory tracking guidance that controls the horizontal positions of the quadrotor to track the desired trajectory by forcing the direction of velocity converge to a reference line pointing to the trajectories, and remains the magnitude of the velocities constant at desired value. The tracking response can be adjusted for different quadrotor dynamics. A nonlinear dynamic model is presented as two subsystems. The roll and pitch angles are stabilized during velocities tracking. Based on this design, a backstepping controller is derived to approach the desired velocities, vertical position and yaw angle and guaranteed by the Lyapunov theory. Simulations are carried out and show the good performance of trajectory tracking abilities and feasibility of the whole guidance system with controller.