The invention discloses a quad-rotor UAV fault tolerance control method based on an adaptive fault estimation observer, and belongs to the field of aviation aircraft control. The method comprises thata fault model of a quad-rotor attitude system is established according to a dynamic model of a quad-rotor UAV by considering a performer fault of a UAV system; a performer of the UAV includes four rotor motors in practicality, faults correspond to the four rotor motors, the fault model is processed, the faults are divided into two groups decoupled mutually, and a final attitude fault model is obtained; according to the provided fault model, the adaptive fault estimation observer is designed, corresponding adaptive laws are provided, the performance fault is estimated, and an H(infinite) method and an interval matrix method are used on external disturbance and parameter nondeterminacy respectively in the design process; and an attitude system error fault model is obtained on the basis of the fault model, a dynamic output feedback fault tolerance controller is designed on the basis of a fault estimated value, and fault tolerance control of the quad-rotor UAV is realized. Influence of the performer fault on performance of the quad-rotor UAV can overcome, and the safety and reliability of the UAV in the flight process are ensured fully.