The high precision navigation is the essential avionics equipment of civil aircraft. Aiming at redundance navigation system of civil aircraft, an integrated navigation method for civil aircraft based on three filter was described. The principle of this method was introduced. Then the first step Kalman filter was used to implement local estimation, and the second step federate Kalman filter was used to implement whole estimation, and the third step whole filter was used to implement optimization estimation. Finally, the simulation of this method was finished.A simulation result demonstrated that this method has higher precision of position and velocity and attitude, which can satisfy the requirement of higher precision civil aircraft navigation.