As a key subsystem in aircraft, electro-hydraulic power and actuation system embodies performance and reliability that is crucial to aircraft safety, maneuverability and flight quality. The substantially increased system redundancy and high volume of dissimilar redundancy further complicate the aircraft electro-hydraulic control and actuation system. This paper presents the reliability model based on three-axis control as well as the reliability assessment method considering the function and performance. Application in several structures of aircraft power and actuation system indicates that the results of proposed method are closer to the actual situation.