The invention provides an aircraft aerodynamic characteristic on-line identification method based on a backtracking self-adaptive algorithm. The aircraft aerodynamic characteristic on-line identification method comprises steps: (1) equivalently transforming the product term of the inverse of a rotational inertia matrix and a moment vector in an aircraft angular velocity kinetic equation into a Phi<T>(k)Theta* form, carrying out discretization processing on the transformed product term, and obtaining an aircraft angular velocity difference equation; wherein Phi<T>(k) represents a signal vector,Theta* represents a parameter truth vector, and the parameter truth vector is a column vector including an aerodynamic characteristic parameter to be identified; (2) establishing a mathematical modelof an angular velocity estimation virtual system, and making an angular velocity estimation error and a parameter estimation error be Phi<T>(k)[Theta(k)-Theta*], wherein Theta(k) represents an estimated value of the parameter truth vector; (3) establishing a backtracking performance formula of the angular velocity estimation error, combining a backtracking updating rule to obtain Phi (k) in realtime, resolving the Theta(k) by means of the backtracking self-adaptive algorithm, making the angular velocity estimation error omega-wave(k) approach zero, and resolving the aerodynamic characteristic parameter to be identified according to the value of the Theta(k). The aircraft aerodynamic characteristic on-line identification method has a lower calculated amount and a lower demand on the computer, and has operability.