Aiming at the problems of Qball2 quad-rotor UAV of under-actuation, uncertain parameters, and strong coupling, a control method is proposed combining Tracking Differentiator (TD) with Linear Active Disturbance Rejection Control (LADRC). The LADRC is composed of two parts:Linear Combination (PD) and Linear Expansion State Observer (LESO).LESO makes real-time observation and dynamic compensation for the internal and external disturbances, thus the complex Qball2 system can be simplified to a series of integral forms. The LADRC parameter tuning is simple, and the introduction of TD makes the system fast and robust. The simulation and Qball2 experiment results show that the designed controller can satisfy the requirements of the system on dynamic performance and steady-state performance.