A mechanical analysis is made to the quad-rotor aircraft, and a mathematical model of 6 degree-of-freedom is established. Then, on the account of the underactuation and strong coupling characteristics of the quad-rotor mathematical model, a control method based on integral backstepping (IBS) and Linear Active Disturbance Rejection Controller (LADRC) is proposed for trajectory tracking and controlling of the quad-rotor aircraft. Firstly, the whole control process is divided into outer-loop position control and inner-loop attitude angle control. Then, for the under-actuated outer-loop position control, the IBS control method adaptable for under-driven system is used; as to the seriously coupled inner-loop attitude angle control, the LADRC control strategy with anti-coupling effect is adopted. The result of experimental simulation shows that the method can realize the trajectory tracking of the quad-rotor aircraft.